4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid amide

ABSTRACT

Disclosed herein are 4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid amide derivatives having a high antagonistic activity against angiotensin II and a high specificity to angiotensin II receptors, intermediates for preparing the derivatives, and antagonists against angiotensin II comprising the derivatives.

BACKGROUND OF THE INVENTION

The present invention relates to 4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid amide derivatives, intermediates for preparing the derivatives, and antagonists against angiotensin II (AII) comprising the derivatives.

Angiotensin II is an octapeptide hormone typically relating to hypertension, central nervous system diseases. It is therefore known that inhibition of the activities of angiotensin II is effective for the treatment of the hypertension and the central nervous system diseases.

As angiotensin II inhibitors, there have been developed a renin inhibitor and an angiotensin-converting enzyme (ACE) inhibitor which inhibit the synthesis of angiotensin II. These inhibitors, however, have the problems that they are incapable of inhibiting the activities of angiotensin produced by other types of enzymes than renin and ACE, and that they may exert adverse effects to the other metabolic systems.

Angiotensin II acts through interaction with a specific receptor present in a cell membrane, so that an angiotensin II receptor antagonist which is capable of inhibiting all of the actions of the generated angiotensin II at the level of interaction with the receptor and gives no influence to the other metabolic systems has been desired as an antagonistic agent which is more specific and has less side effects.

Some peptide analogs such as Saralasin have been reported as angiotensin II receptor antagonists, but they are unsatisfactory in their antagonistic activities and also the area of their applications is limited because of their lack of oral absorptivity.

Recently, non-peptidic angiotensin II receptor antagonists have been reported as the agents free of the said problems. Examples of these antagonists are DuP753, PD123177 (Bio-organic & Medical Chemistry Letters, 1(12), 711-716, 1991) and 4,5,6,7-tetrahydro-1H-imidazo[4,5c]pyridine-6-carboxylic acid derivatives disclosed in U.S. Pat. No. 5,091,390, which are represented by the following structural formulae (1), (2), and (3), respectively: ##STR1## wherein for example, R¹ is hydrogen, R² is CO₂ H, R³ is COCH(Ph)₂, X is NHCO, R⁴ is CO₂ H, and R⁶ is CH₃.

Nevertheless, request for the development of a compound having a higher specificity to the angiotensin II receptors and a higher antagonistic activity against angiotensin II is still rising.

In view of the above, the present inventors have extensive researches for wide range of compounds and, as a result, found that some specific 4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid amide derivatives have a noticeably high antagonistic activity against angiotensin II and a high specificity to angiotensin II receptors as compared with the known compounds. Based on this finding, the present invention has been attained.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, there is provided a compound of the formula (I): ##STR2## or a pharmaceutically acceptable salt thereof; wherein R¹ represents

hydrogen atom,

halogen atom,

C₁ -C₆ alkyl,

C₃ -C₆ alkenyl,

C₃ -C₆ alkynyl,

R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6,

R²⁰ --C(O)-- wherein R²⁰ is as defined above, or

R²⁰ --CH(OH)-- wherein R²⁰ is as defined above;

R² represents carbamoyl, mono- or di-C₁ -C₆ alkylcarbamoyl, or 4- to 6-membered heterocyclic carbamoyl;

R represents amino, carboxy, (1H-tetrazol-5-yl)phenyl, carboxyphenyl, carboxybenzamido, (1H-tetrazol-5-yl)benzamido, carboxyphenylcarbamoyl, or (1H-tetrazol-5-yl)-phenylcarbamoyl;

R³ represents --CH₂ (phenyl), --CH(phenyl)₂, --CH(phenyl)CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl); and

R⁴, R⁷, and R⁸ each represent independently hydrogen atom or C₁ -C₆ alkyl.

In a second aspect of the present invention, there are provided intermediates for producing the compound as defined in the first aspect of the present invention.

In a third aspect of the present invention, there is provided an angiotensin II antagonist comprising the compound as defined in the first aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The compound of the formula (I) or the pharmaceutically acceptable salt thereof have a noticeably high antagonistic activity against angiotensin II and a high specificity to angiotensin II receptors.

Preferred is a compound of the formula (I) or a pharmaceutically acceptable salt thereof wherein R¹ is hydrogen atom or C₁ -C₆ alkyl group; R² is --CONH₂, --CONHCH₃, --CON(CH₃)₂, --CONH(C₂ H₅), --CON(C₂ H₅)₂, ##STR3## R is amino, carboxy, 2-(1H-tetrazol-5-yl)phenyl, 2-carboxyphenyl, 2-carboxybenzamido, 2-(1H-tetrazol-5-yl)benzamido, 2-carboxyphenylcarbamoyl, or 2-(1H-tetrazol-5-yl)phenylcarbamoyl; R³ is --CH(phenyl)₂, --CH₂ (phenyl), --CH(phenyl)CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (p-methoxyphenyl), or --CH₂ (p-hydroxyphenyl); and R⁴, R⁷, and R⁸ each are independently hydrogen atom or C₁ -C₂ alkyl.

The compound of the present invention has an asymmetric carbon atom at the 6-position of the condensed imidazole ring. Accordingly, the present invention includes any single stereoisomer thereof. Also, the present invention includes a mixture of stereoisomers. Preferably, the compound of the present invention is a stereoisomer in which the 6-position of the condensed imidazole ring is S configuration.

The pharmaceutically acceptable salt of the compound of the present invention can be obtained by using an acid or a base which is commonly employed in the field of pharmacy. Preferred examples of the acid include organic and inorganic acids such as hydrochloric acid, sulfuric acid, methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. Preferred examples of the organic base include mono-, di-, or trialkylamines such as methylamine, dimethylamine, and triethylamine, and mono-, di-, or trihydroxyalkylamines such as mono-, di-, or triethanolamine. Preferred examples of the inorganic base include hydroxides, carbonates, and bicarbonates of ammonium, sodium, lithium, potassium, calcium, magnesium, aluminum, zinc, and the like.

The term "halogen atom" used herein means an atom of fluorine, chlorine, bromine, and iodine.

In the present invention, the phenyl group having a substituent may have its substituent or substituents at any of the o-, m-, and p-positions unless otherwise specified.

An example of a process for preparing a compound of the present invention (hereinafter called process A) is shown in Scheme I. ##STR4##

With reference to Scheme I, the process A is described by dividing the process into ten steps (1)-(10).

STEP (1)

A compound of the formula (XI) wherein R¹ is as defined above and Boc stands for tertiary butoxycarbonyl, is reacted with a compound of the formula (X) wherein Y is OH, Cl, Br, or OSO₂ CF₃ ; R⁴ is H or C₁ -C₆ alkyl; R⁶ is NO₂, cyanophenyl, cyano, (1H-tetrazol-5-yl) phenyl, or C₁ -C₃ alkoxycarbonyl; and R⁷ and R⁸ each are independently H or C₁ -C₆ alkyl, at 0° to 60° C. for 10 to 48 hours to obtain a compound of the formula (IX) wherein R¹, R⁴, R⁶, R⁷, R⁸, and Boc are as defined above.

STEP (2)

The compound of the formula (IX) obtained in the step (1) is treated with an acid, such as hydrochloric acid, to obtain a compound of the formula (VIII) wherein R¹, R⁴, R⁶, R⁷, and R⁸ are as defined above.

STEP (3)

To the compound of the formula (VIII), there are added an acid and HCHO, and the mixture is reacted at 10° to 150° C. for 0.5 to 4 hours to obtain a compound of the formula (VII) wherein R¹, R⁴, R⁶, R⁷, and R⁸ are as defined above.

STEP (4)

The compound of the formula (VII) is suspended in an alcohol/trimethyl orthoformate mixture and then HCl is blown into the suspension to carry out reaction at 60° to 100° C. for 4 to 8 hours to obtain a compound of the formula (VI) wherein R¹, R⁴, R⁶, R⁷, and R⁸ are as defined above.

STEP (5)

The compound of the formula (VI) is added to a solution of acetonitrile, chloroform, dimethylformamide, or THF containing carbodiimide, 1-hydroxybenztriazole, diphenylacetic acid, or phenylcyclohexylacetic acid and reacted at 10° to 40° C. for 10 to 48 hours to obtain a compound of the formula (V) wherein R¹, R⁴, R⁶, R⁷, and R⁸ are as defined above; and R³ is --CH(phenyl)₂, --CH(phenyl)(cyclohexyl), --CH₂ (phenyl), --CH₂ CH₂ (phenyl), --CH(phenyl)CH₃, --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl).

STEP (6)

An alkali, e.g. NaOH, is added to the compound of the formula (V) to obtain a compound of the formula (IV) wherein R¹, R³, R⁴, R⁶, R⁷, and R⁸ are as defined above

STEP (7)

A nitrogen-containing compound is added to the compound of the formula (IV) and the mixture is reacted at 10° to 40° C. for 10 to 24 hours to obtain a compound of the formula (Ill) wherein R¹, R³, R⁴, R⁶, R⁷, and R⁸ are as defined above; and R^(2') is amino, mono- or di-C₁ -C₆ alkylamino, or 4- to 6-membered heterocyclic amino.

When R⁶ is (1H-tetrazol-5-yl)phenyl, it is obtained a compound of the formula (I) wherein R is (1H-tetrazol-5-yl)phenyl, in this step.

STEP (8)

Tin chloride dihydrate is added to the compound of the formula (III) wherein R⁶ is NO₂ and the mixture is reacted at 40° to 100° C. for 10 to 120 minutes to obtain a compound of the formula (II) wherein R¹, R^(2'), R³, R⁴, R⁷, and R⁸ are as defined above.

STEP (9)

A benzoic acid derivative is reacted with the compound of the formula (II) at 10° to 40° C. for 10 to 24 hours to obtain a compound of the formula (I) wherein R¹, R^(2'), R³, R⁴, R⁷, and R⁸ are as defined above.

STEP (10)

When R₆ is cyanophenyl, there can be obtained a compound of the formula (I) wherein X is a C--C single bond, by hydrolyzing the compound of the formula (III).

A compound of the formula (XI) (raw material) can be obtained by the method described in J. Am. Chem. Soc., 114 (5), 1906-1908, 1992.

A compound of the formula (X) (raw material) can be obtained, for example, by the method described in J. Med. Chem., 33, 1312-1329, 1990, J. Med. Chem., 34, 2525-2547, 1991, J. Med. Chem., 34, 3248-3260, 1991, etc.

Conversion of substituents may be made by the conventional method available to one ordinarily skilled in the art.

Another example of a process for producing the compound of the present invention (hereinafter referred to as process B) is described in Scheme II. ##STR5##

With reference to Scheme II the process B is described by dividing the process into 19 steps (a)-(s).

STEP (a)

A compound of the formula (XXIII) is reacted with a tertiary amine such as Tr (triphenylmethyl) chloride and triethylamine in a solvent such as ether, THF (tetrahydrofuran), dioxane, methylene chloride, and chloroform at 10° to 60° C. for 2 to 24 hours to obtain a compound of the formula (XXII). The compound of the formula (XXIII) is commercially available.

STEP (b)

The compound of the formula (XXII) is reacted with a reducing agent such as lithium aluminum hydride in a solvent such as ether, THF, and dioxane at 0° to 40° C. for 0.1 to 1 hour to obtain a compound of the formula (XXI).

STEP (c)

The compound of the formula (XXI) is reacted with TBDMS (tertiary butyldimethylsilyl) chloride and imidazole in a solvent such as DMF (dimethylformamide) at 0° to 40° C. for 0.5 to 6 hours to obtain a compound of the formula (xx).

STEP (d)

The compound of the formula (XX) is dissolved in a solvent such as ether, THF, and dioxane in an atmosphere of an inert gas such as nitrogen or argon gas, and reacted with a R¹ halide (chloride, bromide, or iodide) in the presence of a base such as butyl lithium (normal, secondary, or tertiary) and HMPA (hexamethylphosphoramide) at 0° to 40° C. for 0.1 to 6 hours to obtain a compound of the formula (XIX).

STEP (e)

An acid such as hydrochloric acid, is added to the compound of the formula (XIX) and the mixture is reacted at 10° to 120° C. for 0.5 to 6 hours to obtain a compound of the formula (XVIII). This compound may be isolated. When it is not isolated, an aqueous HCHO solution is directly added thereto, and the mixture is reacted at 10 to 120 for 0.5 to 6 hours to obtain a compound of the formula (XVII).

STEP (f)

The compound of the formula (XVII) is added to a solution of acetonitrile, chloroform, or THF containing carbodiimide, 1-hydroxybenztriazole, and R³ COOH, and reacted at 10° to 60° C. for 1 to 48 hours to obtain a compound of the formula (XVI).

STEP (g)

The compound of the formula (XVI) and a compound of the formula (X) are reacted in a solvent such as acetone, DMF, ether, THF, and chloroform in the presence of an appropriate base such as anhydrous potassium carbonate at 10° to 60° C. for 1 to 48 hours to obtain a compound of the formula (XV).

STEP (h)

The compound of the formula (XV) is reacted with an oxidizing agent such as chromic acid in a solvent such as acetone, methylene chloride, and chloroform at 10° to 40° C. for 0.1 to 3 hours to obtain a compound of the formula (XIV).

STEP (i)

The compound of the formula (XIV) is added to a solution of acetonitrile, chloroform, or THF containing carbodiimide, 1-hydroxybenztriazole, and linear or cyclic alkylamine, and reacted at 10° to 60° C. for 1 to 48 hours to obtain a compound of the formula (XIII).

STEP (j)

When R⁶ is methoxycarbonyl, an alkali such as a sodium hydroxide is added to a solution of the compound of the formula (XIV) in an alcohol, ether, THF, or a mixture thereof, and reacted at 10° to 40° C. for 1 to 24 hours to obtain a compound of the formula (I') wherein R¹⁰ is carboxy.

STEP (k)

When R⁶ is nitro, tin chloride, or tin chloride dihydrate is added to a solution of the compound of the formula (XIII) in ethyl acetate, an alcohol, or a mixture thereof, and reacted in an atmosphere of an inert gas such as nitrogen or argon gas at 10° to 100° C. for 0.1 to 1 hour to obtain a compound of the formula (I') wherein R¹⁰ is amino.

STEP (l)

When R⁶ is cyanophenyl, trimethyltin azide or tributyltin azide is added to a solution of the compound of the formula (XIII) in toluene or xylene, and the mixture is reacted in an atmosphere of an inert gas such as nitrogen or argon gas at 100° to 120° C. for 12 to 120 hours, followed by a treatment with an acid such as hydrochloric acid to obtain a compound of the formula (I) wherein R¹⁰ is 1H-tetrazol-5-yl) phenyl.

STEP (m)

When R⁶ is ((1-triphenylmethyl) -1H-tetrazol-5-yl)phenyl, the compound of the formula (XIII) is dissolved in a solvent such as THF and dioxane, and an acid such as hydrochloric acid is added to the solution. Then, the mixture is reacted at 10° to 100° C. for 0.1 to 6 hours to obtain a compound of the formula (I) wherein R¹⁰ is (1H-tetrazol-5-yl)phenyl.

STEP (n)

When R¹⁰ is carboxy or amino, the compound of the formula (I') is dissolved in a solvent such as chloroform, acetonitrile, THF, and dioxane, and reacted by adding a compound having a required group at 10° to 60° C. for 1 to 24 hours to obtain a compound of the formula (I).

STEP (o)

The compound of the formula (XIX) is dissolved in a solvent such as THF and ether, and reacted with tetra-n-butylammonium fluoride at 0° to 40° C. for 0.5 to 6 hours to obtain a compound of the formula (XXIV).

STEP (p)

The compound of the formula (XXIV) is dissolved in DMF, and reacted with PDC (pyridinium dichromate) at 0° to 40° C. for 0.5 to 24 hours to obtain a compound of the formula (XXV).

STEP (q)

An acid such as hydrochloric acid is added to the compound of the formula (XXV) and the mixture is reacted at 10° to 120° C. for 0.5 to 6 hours to obtain a compound of the formula (XXV'). This compound (XXV') may be isolated. When it is not isolated, an HCHO solution is directly added thereto and the mixture is reacted at 10° to 120° C. for 0.5 to 6 hours to obtain a compound of the formula (XXVI).

STEP (r)

The compound of the formula (XXVI) is added to a solution of acetonitrile, chloroform, or THF containing carbodiimide, dimethylformamide, 1-hydroxybenztriazole, and R³ COOH, and reacted at 10° to 60° C. for 1 to 48 hours to obtain a compound of the formula (XXVII).

STEP (s)

The compound of the formula (XXVlI) is reacted with a compound of the formula (X) in a solvent such as acetone, DMF, ether, THF, and chloroform in the presence of an appropriate base such as anhydrous potassium carbonate at 10° to 60° C. for 1 to 48 hours to obtain a compound of the formula (XlV).

The compound of the formula (X) can be obtained, for instance, by a method described in J. Med. Chem., 34, 2525-2547, 1991, J. Med. Chem., 35, 4027-4038, 1992, etc.

The present invention also provides the following intermediate compounds (A) to (E) for the preparation of the compound represented by the formula (I) of the present invention.

(A) A compound of the formula (III'): ##STR6## or a salt thereof; wherein R¹ represents

hydrogen atom,

halogen atom,

C₁ -C₆ alkyl,

C₃ -C₆ alkenyl,

C₃ -C₆ alkynyl,

R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6,

R²⁰ --C(O)-- wherein R²⁰ is as defined above, or

R²⁰ --CH(OH)-- wherein R²⁰ is as defined above;

R⁴ is hydrogen atom or C₁ -C₆ alkyl;

R⁶ is nitro, (1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, cyano, C₁ -C₃ alkoxycarbonyl, or cyanophenyl;

R⁷ and R⁸ each are independently hydrogen atom or C₁ -C₆ alkyl;

R⁹ is hydrogen atom or t-butoxycarbonyl; and

R¹⁰ is hydrogen atom or C₁ -C₆ alkyl.

In the formula (XIII'), preferably R¹ is hydrogen atom or C₁ -C₆ alkyl; R⁴ is hydrogen atom or C₁ -C₂ alkyl; R⁶ is nitro, 2-(1-trifluoromethyl-1H-tetrazol-5-yl)phenyl, or 2-cyanophenyl; R⁷ and R⁸ each are independently hydrogen atom or C₁ -C₆ alkyl; and R¹⁰ is hydrogen atom or C₁ -C₆ alkyl.

(B) A compound of the formula (XXVIII): ##STR7## or a salt thereof; wherein R¹ represents

hydrogen atom,

halogen atom,

C₁ -C₆ alkyl,

C₃ -C₆ alkenyl,

C₃ -C₆ alkynyl,

R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6,

R²⁰ --C(O)-- wherein R²⁰ is as defined above, or

R²⁰ --CH(OH)-- wherein R²⁰ is as defined above;

R¹⁵ represents --CH₂ --R¹⁷ wherein R¹⁷ represents hydroxy or t-butyldimethylsilyloxy, or --C(O)--R¹⁷ wherein R¹⁷ is as defined above; and

R¹⁶ represents hydrogen atom or triphenylmethyl;

with proviso that when R¹ and R¹⁶ are both hydrogen atom, R¹⁵ is not --CH₂ --OH, and that when R¹ is hydrogen atom or methyl and R¹⁶ is hydrogen atom, R¹⁵ is not --COOH.

(C) A compound of the formula (XXIX): ##STR8## or a salt thereof; wherein R¹ represents

hydrogen atom,

halogen atom,

C₁ -C₆ alkyl,

C₃ -C₆ alkenyl,

C₃ -C₆ alkynyl,

R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6,

R²⁰ --C(O)-- wherein R²⁰ is as defined above, or

R²⁰ --CH(OH)-- wherein R²⁰ is as defined above;

R¹⁵ represents --CH₂ --R¹⁷ wherein R¹⁷ represents hydroxy or t-butyldimethylsilyloxy, or --C(O)--R¹⁷ wherein R¹⁷ is as defined above;

R³ represents hydrogen atom, --COCH₂ (phenyl), --COCH(phenyl)₂, --COCH(phenyl)CH₃, --COCH(phenyl)(cyclohexyl), --COCH₂ CH₂ (phenyl), --COCH₂ (C₁ -C₆ alkoxyphenyl), or --COCH₂ (hydroxyphenyl);

with proviso that when R¹ and R^(3') are both hydrogen atom, R¹⁵ is not --COOH.

In the formula (XXIX), preferably R¹ is hydrogen atom or C₁ -C₆ alkyl; R¹⁵ is --COOH; and R^(3') is --COCH(phenyl)₂ or --COCH(phenyl)(cyclohexyl).

(D) A compound of the formula (XXX): ##STR9## or a salt thereof; wherein R¹ represents

hydrogen atom,

halogen atom,

C₁ -C₆ alkyl,

C₃ -C₆ alkenyl,

C₃ -C₆ alkynyl,

R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6,

R²⁰ --C(O)-- wherein R²⁰ is as defined above, or

R²⁰ --CH(OH)-- wherein R²⁰ is as defined above;

R^(3') represents hydrogen atom, --COCH₂ (phenyl), --COCH(phenyl)₂, --COCH(phenyl)CH₃, --COCH(phenyl)(cyclohexyl), --COCH₂ CH₂ (phenyl), --COCH₂ (C₁ -C₆ alkoxyphenyl), or --COCH₂ (hydroxyphenyl);

R⁴, R⁷, and R⁸ each represent independently hydrogen atom or C₁ -C₆ alkyl;

R⁶ represents nitro, (1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, cyano, C₁ -C₃ alkoxycarbonyl, or cyanophenyl; and

R¹⁵ represents --CH₂ --R¹⁹ wherein R¹⁹ represents hydrogen atom or C₁ -C₆ alkyl group, or --C(O)--R¹⁹ wherein R¹⁹ is as defined above.

In the formula (XXX), preferably R¹ is hydrogen atom or C₁ -C₆ alkyl; R^(3') is --COCH(phenyl)₂ or --COCH(phenyl)(cyclohexyl); R⁶ is nitro, 2-(1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, cyano, methoxycarbonyl, or 2-cyanophenyl; R⁴, R⁷, and R⁸ each are independently hydrogen atom or C₁ -C₂ alkyl; and R¹⁹ is hydrogen atom or C₁ -C₂ alkyl.

(E) A compound of the formula (XIII): ##STR10## or a salt thereof; wherein R¹ represents

hydrogen atom,

halogen atom,

C₁ -C₆ alkyl,

C₃ -C₆ alkenyl,

C₃ -C₆ alkynyl,

R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6,

R²⁰ --C(O)-- wherein R²⁰ is as defined above, or

R²⁰ --CH(OH)-- wherein R²⁰ is as defined above;

R^(2') represents amino, mono or di-C₁ -C₆ alkylamino, or 4- to 6-membered heterocyclic amino;

R³ represents --CH₂ (phenyl), --CH(phenyl)₂, --CH(phenyl)CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl);

R⁴, R⁷ and R⁸ each represent independently hydrogen atom or C₁ -C₆ alkyl; and

R⁶ represents nitro, (1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, C₁ -C₃ alkoxycarbonyl, cyano, or 2-cyanophenyl.

In the formula (XIII), preferably R¹ is hydrogen atom or C₁ -C₆ alkyl; R² is --NH₂, --NHCH₃, --N(CH₃)₂, --NH(C₂ H₅), N(C₂ H₅)₂, ##STR11## R³ is --CH(phenyl)₂, or --CH(phenyl)(cyclohexyl); R⁴, R⁷, and R⁸ each are independently hydrogen atom or C₁ -C₂ alkyl; and R⁶ is nitro, 2-(1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, methoxycarbonyl, cyano, or 2-cyanophenyl.

The intermediate compounds of the present invention each have an asymmetric carbon atom at the 6-position of the condensed imidazole ring or the corresponding position. These intermediate compounds, therefore, include the single stereoisomer thereof. Also, the present invention includes a mixture of stereoisomers. In the present invention, these intermediate compounds are preferably the stereoisomers in which the 6-position of the condensed imidazole ring or the corresponding position is S configuration.

The salts of the above intermediate compounds can be obtained by using an acid or a base which is capable of chemically forming a salt with the intermediate compounds.

The formula (XIII') of (A) includes the formulae (IX) and (VIII) in the process A described above, and the formula (XXVIII) of (B) includes the formulae (XVIII), (XIX), (XXIV), (XXV), and (XXIII) in the process B described above. Also, the formula (XXIX) of (C) includes the formulae (XVII), (XVI), (XXVI), and (XXVII) in the process B, and the formula (XXX) of (D) includes the formulae (VII), (VI), (V), and (IV) in the process B. Therefore, these intermediate compounds (A) to (E) can be produced according to the process A or B.

The present invention further provides an angiotensin II antagonist comprising a compound of the formula (I) or a pharmaceutically acceptable salt thereof.

The compound of the present invention produces its pharmacological effect by competing with the receptor of angiotensin II and thereby inhibiting or suppressing the action of angiotensin II.

Particularly, the compound competes specifically with the AT₁ receptor (when R¹ in the formula (I) is not hydrogen atom) and the AT₂ receptor (when R¹ is hydrogen atom), which are known as angiotensin II receptors, according to the difference of R¹ in the formula (I). Also, as apparent from the Examples described later, the compound has a notably high antagonistic activity as compared with the known compounds.

Thus, the compound of the present invention is useful as a therapeutic agent for the diseases of the cardiovascular system and the central nervous system such as hypertension, heart diseases (cardiac hypertrophy, heart failure, myocardial infarction, et.), cerebral apoplexy, etc. The compound is also useful as a reagent or an agent for the studies on the role of angiotensin and its receptors.

When a substance of the present invention was given orally to the mice at a dosage of 300 mg/kg and they were observed for one week, none of the mice died in this period. This confirms that the compound of the present invention has no acute toxicity.

EXAMPLES

In the following, the present invention will be described with reference to the examples thereof. It is to be understood, however, that these examples are merely intended to be illustrative and not to be construed as limiting the scope of the invention.

Abbreviations used herein are as follows: cyc, cyclic; c-Hex, cyclohexyl; Ph, phenyl; Me, methyl; Et, ethyl; iPr, i-propyl; nPr, n-propyl; nBu, n-butyl; nHex, n-hexyl; Tr, triphenylmethyl.

EXAMPLE 1 Process A, Step (1) Synthesis of 3-(3-methyl-4-nitrophenyl)methyl-N-t-butoxycarbonyl-L-histidine methyl ester (IX-2)

Trifluoromethanesulfonic anhydride (10.00 g, 0.0354 mol) and dry methylene chloride (60 ml) were placed into a 500 ml separable flask having its interior atmosphere replaced with well dried nitrogen gas, and cooled to -70° C. Then a solution of 3-methyl-4-nitrobenzyl alcohol (5.34 g, 0.0325 mol) and N,N-diisopropylethylamine (6.2 ml, 0.0356 mol) in dry methylene chloride (40 ml) was added dropwise over a period of 15 minutes, followed by stirring for 30 minutes, after which a solution of N,1-bis-t-butoxycarbonyl-L-histidine methyl ester (XI-2) (10.00 g, 0.0271 mol) in dry methylene chloride (40 ml) was further added dropwise over a period of 20 minutes. Thereafter, the reaction flask was taken out of the cooling bath and the mixture was stirred at room temperature for 6 hours. The reaction mixture during rapid stirring was poured into a 0.2M phosphate buffer solution (about 400 ml) to separate the methylene chloride layer, and the residue was washed with a 0.2M phosphate buffer solution (about 400 ml), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain an orange-colored oily material (12.07 g). This crude oily material was purified by silica gel column chromatography (LiChroprep Si60, 300 g, chloroform/methanol=30/1) to obtain the objective compound (IX-2) (4.45 g; yield: 39.3%) as a light-yellow oily material.

There were similarly synthesized the corresponding compounds by using the raw compounds of the formulae (XI) and (X) wherein R¹ was H, Et, iPr, nBu, or nHex, and R⁴, R⁶, R⁷, R⁸, and Y were as shown in Table 1 below.

                  TABLE 1                                                          ______________________________________                                         Compound                                                                       No.     R.sup.4  R.sup.6  R.sup.7                                                                               R.sup.8                                                                             Y                                        ______________________________________                                         X-1     H        NO.sub.2 H      H    OH                                       X-2     Me       NO.sub.2 H      H    OH                                       X-3     H        2-CN-Ph  H      H    OH                                       X-4     H        2-CN-Ph  H      H    Br                                       X-5     Me       2-CN-Ph  H      H    Br                                       X-6     H        2-CN-Ph  H      H    OSO.sub.2 CF.sub.3                       X-7     Me       NO.sub.2 Me     Me   OH                                       X-8     Me       2-CN-Ph  Me     Me   Br                                       ______________________________________                                    

EXAMPLE 2 Process A, Step (2) Synthesis of 3-(3-methyl-4-nitrophenyl)methyl-L-histidine dihydrochloride (VIII-2)

A 6N hydrochloric acid solution (54.5 ml) was added to 3-(3-methyl-4-nitrophenyl)methyl-N-t-butoxycarbonyl-L-histidine methyl ester (IX-2) (1.3626 g, 0.00326 mol), and the mixture was refluxed under heating on a 120° C. oil bath for 2.5 hours. The resulting solution was cooled and then concentrated to obtain the objective compound (VIII-2) (1.1406 g; yield: 92.9%) as a light-brown oily material.

EXAMPLE 3 Process A, Step (3) Synthesis of (S) -1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid dihydrochloride (VII-2)

A 1N hydrochloric acid solution (13.7 ml) and a 37% formaldehyde solution (0.74 ml, 0.00907 mol) were added to 3-(3-methyl-4-nitrophenyl)methyl-L-histidine dihydrochloride (VIII-2) (1.1406 g, 0.00302 mol), and the mixture was stirred first at room temperature for half an hour and then on a 120° C. oil bath for 1.5 hours. The mixture was then cooled and concentrated to obtain the objective compound (VII-2) (1.1538 g; yield: 98.0%) as yellowish brown crystals (decomposed at 256.5°-258° C).

EXAMPLE 4 Process A, Step (4) Synthesis of (S)-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid methyl ester (VI-2)

(S)-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid dihydrochloride (VII-2) (1.1538g, 0.00296 mol) was suspended in dry methanol (46 ml) and trimethylorthoformate (4.6 ml). Hydrogen chloride was blown into the suspension to saturation under ice cooling and stirring. The reaction solution was then stirred on a 90° C. oil bath for 6 hours, cooled, and concentrated. The resulting yellowish brown oily material (0.7456 g) was purified by silica gel column chromatography (Kiesegel 60, 60 g, chloroform/methanol= 15/1) to obtain the objective compound (VI-2) (0.7076 g; yield: 72.3%) as an orange oily material.

Similarly to Examples 1-4, there were synthesized the compounds of Table 2.

                  TABLE 2                                                          ______________________________________                                         Compound                                                                       No.       R.sup.1  R.sup.4                                                                               R.sup.6  R.sup.7                                                                             R.sup.8                                ______________________________________                                         VI-1      H        H      NO.sub.2 H    H                                      VI-2      H        Me     NO.sub.2 H    H                                      VI-3      Et       Me     NO.sub.2 H    H                                      VI-4      iPr      Me     NO.sub.2 H    H                                      VI-5      nBu      Me     NO.sub.2 H    H                                      VI-6      nHex     Me     NO.sub.2 H    H                                      VI-7      H        H      2-CN-Ph  H    H                                      VI-8      nBu      H      2-CN-Ph  H    H                                      VI-9      nBu      Me     2-CN-Ph  H    H                                       VI-10    nBu      Me     NO.sub.2 Me   Me                                      VI-11    nBu      Me     2-CN-Ph  Me   Me                                     ______________________________________                                    

EXAMPLE 5 Process A, Step (5) Synthesis of (S)-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid methyl ester (V-2)

Acetonitrile (16 ml) was added to a mixture of N,N'-dicyclohexylcarbodiimide (DCCI) (2.1080 g, 0.01022 mol), 1-hydroxybenzotriazole (HBTA) (1.3806 g, 0.01022 mol), and diphenylacetic acid (2.1685 g, 0.01022 mol), followed by stirring at room temperature for 20 minutes. A solution of (S)-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid methyl ester (VI-2) (2.7000 g, 0.00817 mol) in acetonitrile (14 ml) was added to the suspension, and the mixture was stirred at room temperature for 21 hours. An insoluble portion in the reaction mixture was filtered out and washed with acetonitrile, and then the filtrate and washings were joined and concentrated. The residue was dissolved in methylene chloride (40 ml), washed with a 10% sodium carbonate solution and a saturated brine, then dried over sodium sulfate and concentrated to obtain an orange oily material (4.5203 g). This crude oily material was purified by silica gel column chromatography (Kieselgel 60, 270 g, chloroform/methanol=60/11) to obtain the objective compound (V-2) (2.8250 g; yield: 65.9%) as colorless crystals (top: 174.5°-177° C.).

EXAMPLE 6 Process A, Step (6) Synthesis of (S)-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine- 6-carboxylic acid (IV-2)

A 1N sodium hydroxide solution (5.7 ml) was added to a solution of (S)-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5c]pyridine-6-carboxylic acid methyl ester (V-2) (2.8250 g, 0.00539 mol) in tetrahydrofuran/methanol (3/1, 17 ml), and the mixture was left at room temperature for 6 hours. The reaction mixture was concentrated, and the residue was weakly acidified by adding a 1N hydrochloric acid solution (6.0 ml) and then extracted with methylene chloride. The methylene chloride layer was washed with a saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain the objective compound (IV-2) (2.5558 g; yield: 93.0%) as a light-yellow viscous oily material. MS (EI) 492 (M-18).

The compounds of Table 3 were synthesized in the similar way to Examples 5 and 6.

                                      TABLE 3                                      __________________________________________________________________________     Compound                                                                       No.    R.sup.1                                                                           R.sup.3    R.sup.4                                                                           R.sup.6                                                                              R.sup.7                                                                           R.sup.8                                       __________________________________________________________________________     IV-1   H  CH(Ph).sub.2                                                                              H  NO.sub.2                                                                             H  H                                             IV-2   H  CH(Ph).sub.2                                                                              Me NO.sub.2                                                                             H  H                                             IV-3   H  CH(Ph)(cycC.sub.6 H.sub.11)                                                               Me NO.sub.2                                                                             H  H                                             IV-4   Et CH(Ph).sub.2                                                                              Me NO.sub.2                                                                             H  H                                             IV-5   iPr                                                                               CH(Ph).sub.2                                                                              Me NO.sub.2                                                                             H  H                                             IV-6   nBu                                                                               CH(Ph).sub.2                                                                              Me NO.sub.2                                                                             H  H                                             IV-7   nhex                                                                              CH(Ph).sub.2                                                                              Me NO.sub.2                                                                             H  H                                             IV-8   H  CH(Ph).sub.2                                                                              H  2-CN-Ph                                                                              H  H                                             IV-9   nBu                                                                               CH(Ph).sub.2                                                                              H  2-CN-Ph                                                                              H  H                                              IV-10 nBu                                                                               CH(Ph).sub.2                                                                              Me 2-CN-Ph                                                                              H  H                                              IV-11 nBu                                                                               CH(Ph).sub.2                                                                              Me NO.sub.2                                                                             Me Me                                             IV-12 nBu                                                                               CH(Ph).sub.2                                                                              Me 2-CN-Ph                                                                              Me Me                                            __________________________________________________________________________

EXAMPLE 7 Process A, Step (7) Synthesis of (S)-N,N-dimethyl-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[[4,5-c]pyridine-6-carboxamide (III-2)

Acetonitrile (40 ml) was added to a mixture of (S)-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl) methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid (IV-2) (2.5558 g, 0.00501 mol), DCCI (1.2916 g, 0.00626 mol) and HBTA (0.8456 g, 0.00626 mol), and the mixture was stirred at room temperature for 20 minutes. Dimethylamine hydrochloride (0.4488 g, 0.00626 mol) was added to the resulting suspension, and the mixture was stirred at room temperature for 18 hours. An insoluble portion in the reaction solution was filtered out and washed with acetonitrile. The filtrate and washings were joined and concentrated. The residue was dissolved in chloroform (40 ml), washed with a 10% sodium carbonate solution and a saturated brine, then dried over sodium sulfate, and concentrated to obtain a light-yellow oily material (4.3025 g). This crude oily material was purified by silica gel column chromatography (Kieselgel 60, 220 g, chloroform/methanol=60/1) to obtain the objective compound (III-2) (2.3636 g; yield: 87.8%) as a light-yellow viscous oily material. MS (EI): 538 (M+1).

There were similarly synthesized the compounds of Table 4.

                                      TABLE 4                                      __________________________________________________________________________     Compound                                                                       No.   R.sup.1                                                                           R.sup.2 '                                                                             R.sup.3                                                                               R.sup.4                                                                           R.sup.6                                                                             R.sup.7                                                                           R.sup.8                                      __________________________________________________________________________     III-1 H  NMe.sub.2                                                                             CH(Ph).sub.2                                                                          H  NO.sub.2                                                                            H  H                                            III-2 H  NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                            III-3 H  NEt.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                            III-4 H  NMe.sub.2                                                                             CH(Ph)(cyc                                                                            Me NO.sub.2                                                                            H  H                                                            C.sub.6 H.sub.11)                                              III-5 H  cycNC.sub.4 H.sub.8                                                                   CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                            III-6 H  cycNC.sub.5 H.sub.10                                                                  CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                            III-7 H  cycNC.sub.4 H.sub.8 O                                                                 CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                            III-8 H  NH2    CH(Ph).sub.2                                                                          H  NO.sub.2                                                                            H  H                                            III-9 H  NHME   CH(Ph).sub.2                                                                          H  NO.sub.2                                                                            H  H                                             III-10                                                                              Et NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                             III-11                                                                              iPr                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                             III-12                                                                              nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                             III-13                                                                              nhex                                                                              NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            H  H                                             III-14                                                                              H  NMe.sub.2                                                                             CH(Ph).sub.2                                                                          H  2-CN-Ph                                                                             H  H                                             III-15                                                                              nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          H  2-CN-Ph                                                                             H  H                                             III-16                                                                              nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-CN-Ph                                                                             H  H                                             III-17                                                                              nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me NO.sub.2                                                                            Me Me                                            III-18                                                                              nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-CN-Ph                                                                             Me Me                                           __________________________________________________________________________

EXAMPLE 8 Process A, Step (8) Synthesis of (S)-1-(4-amino-3-methylphenyl)methyl-N,N-dimethyl-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxamide (II-2)

(S)-N,N-dimethyl-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxamide (III-2) (2.3636 g, 0.00440 mol) was dissolved in a mixture of 28 ml of ethyl acetate and 5 ml of methanol, followed by addition of tin chloride dihydrate (4.9580 g, 0.0220 mol) and agitation of the solution on an 80° C. oil bath in a stream of nitrogen for 30 minutes. The reaction mixture was cooled, neutralized by adding a 5% sodium carbonate solution, and concentrated. The residue was extracted with chloroform. The chloroform layer was washed with water, dried over sodium sulfate, and then concentrated to obtain a light-yellow foamy material (2.2368 g). This material was purified by silica gel column chromatography (Kieselgel 60, 120 g, chloroform methanol=50/1) to obtain the objective compound (II-2) (2.0077 g; yield: 90.0%) as a white foamy material. MS (EI): 508 (M+1).

There were similarly synthesized the compounds of Table 5.

                  TABLE 5                                                          ______________________________________                                         Compound                                                                       No.    R.sup.1                                                                               R.sup.2 '  R.sup.3  R.sup.4                                                                             R.sup.7                                                                             R.sup.8                            ______________________________________                                         II-1   H      NMe.sub.2  CH(Ph).sub.2                                                                            H    H    H                                  II-2   H      NMe.sub.2  CH(Ph).sub.2                                                                            Me   H    H                                  II-3   H      NEt.sub.2  CH(Ph).sub.2                                                                            Me   H    H                                  II-4   H      NMe.sub.2  CH(Ph)(cyc                                                                              Me   H    H                                                           C.sub.6 H.sub.11)                                     II-5   H      cycNC.sub.4 H.sub.8                                                                       CH(Ph).sub.2                                                                            Me   H    H                                  II-6   H      cycNC.sub.5 H.sub.10                                                                      CH(Ph).sub.2                                                                            Me   H    H                                  II-7   H      cycNC.sub.4 H.sub.8 O                                                                     CH(Ph).sub.2                                                                            Me   H    H                                  II-8   H      NH.sub.2   CH(Ph).sub.2                                                                            H    H    H                                  II-9   H      NHMe       CH(Ph).sub.2                                                                            H    H    H                                   II-10 Et     NMe.sub.2  CH(Ph).sub.2                                                                            Me   H    H                                   II-11 iPr    NMe.sub.2  CH(Ph).sub.2                                                                            Me   H    H                                   II-12 nBu    NMe.sub.2  CH(Ph).sub.2                                                                            Me   H    H                                   II-13 nhex   NMe.sub.2  CH(Ph).sub.2                                                                            Me   H    H                                   II-14 nBu    NMe.sub.2  CH(Ph).sub.2                                                                            Me   Me   Me                                 ______________________________________                                    

EXAMPLE 9 Process A, Step (9) Synthesis of (S)-1-(4-(2-carboxybenzoylamino)-3-methylphenyl)methyl-N,N-dimethyl-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxamide (I-2)

A solution of phthalic acid (0.7223 g, 0.00435 mol) in ethyl acetate (10 ml) was added to a solution of (S)-1-(4-amino-3-methylphenyl)methyl-N,N-dimethyl-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo-[4,5-c]pyridine-6-carboxamide (II-2) (2.0077 g, 0.00396 mol) in ethyl acetate (30 ml) with stirring at room temperature. The mixture was stirred at room temperature for 23 hours, followed by filtration of the reaction mixture. The resulting white solid was washed with ethyl acetate (about 20 ml) and dried to obtain the objective compound (I-2, Compound No. 2) (2.4107 g; yield: 93.0%). MS 637 (EI): (M-18).

There were similarly synthesized the compounds of Table 6.

                                      TABLE 6                                      __________________________________________________________________________     Compound                                                                       No.   R.sup.1                                                                           R.sup.2 '                                                                             R.sup.3                                                                               R.sup.4                                                                           R.sup.                                                                               R.sup.7                                                                           R.sup.8                                                                           MS(EI)                                   __________________________________________________________________________     I-1   H  NMe.sub.2                                                                             CH(Ph).sub.2                                                                          H  2-carboxy-                                                                           H  H  623(M-18)                                                          benzamido                                            I-2   H  NM 2   CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  637(M-18)                                                          benzamido                                            I-3   H  NEt.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  665(M-18)                                                          benzamido                                            I-4   H  NMe.sub.2                                                                             CH(Ph)(cyc                                                                            Me 2-carboxy-                                                                           H  H  643(M-18)                                                C.sub.6 H.sub.11)                                                                        benzamido                                            I-5   H  cycNC.sub.4 H.sub.8                                                                   CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  663(M-18)                                                          benzamido                                            I-6   H  cycNC.sub.5 H.sub.10                                                                  CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  677(M-18)                                                          benzamido                                            I-7   H  cycNC.sub.4 H.sub.8 O                                                                 CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  679(M-18)                                                          benzamido                                            I-8   H  NH.sub.2                                                                              CH(Ph).sub.2                                                                          H  2-carboxy-                                                                           H  H  595(M-18)                                                          benzamido                                            I-9   H  NHME   CH(Ph).sub.2                                                                          H  2-carboxy-                                                                           H  H  609(M-18)                                                          benzamido                                             I-10 Et NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  665(M-18)                                                          benzamido                                             I-11 iPr                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  679(M-18)                                                          benzamido                                             I-12 nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  693(M-18)                                                          benzamido                                             I-13 nBu                                                                               NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           Me Me 721(m-18)                                                          benzamido                                             I-14 nHex                                                                              NMe.sub.2                                                                             CH(Ph).sub.2                                                                          Me 2-carboxy-                                                                           H  H  721(M-18)                                                          benzamido                                            __________________________________________________________________________

The results of elementary analysis of the compounds of Table 6 are shown in Table 7.

                  TABLE 7                                                          ______________________________________                                         Com-                                                                           pound Elementary Calcd. for                                                    No.   analysis   (C, H, N) (%)                                                                               Found (C, H, N) (%)                              ______________________________________                                         I-1   C.sub.38 H.sub.35 N.sub.5 O.sub.5                                                         71.12, 5.50,                                                                               10.91                                                                               71.01,                                                                               5.57,                                                                               10.90                             I-2   C.sub.39 H.sub.37 N.sub.5 O.sub.5                                                         71.43, 5.69,                                                                               10.68                                                                               71.34,                                                                               5.73,                                                                               10.70                             I-3   C.sub.41 H.sub.41 N.sub.5 O.sub.5                                                         72.02, 6.04,                                                                               10.24                                                                               71.93,                                                                               6.10,                                                                               10.22                             I-4   C.sub.39 H.sub.43 N.sub.5 O.sub.5                                                         70.78, 6.55,                                                                               10.58                                                                               70.70,                                                                               6.62,                                                                               10.55                             I-5   C.sub.41 H.sub.39 N.sub.5 O.sub.5                                                         72.23, 5.76,                                                                               10.27                                                                               72.11,                                                                               5.89,                                                                               10.25                             I-6   C.sub.42 H.sub.41 N.sub.5 O.sub.5                                                         72.50, 5.94,                                                                               10.06                                                                               72.39,                                                                               6.01,                                                                               10.04                             I-7   C.sub.41 H.sub.39 N.sub.5 O.sub.6                                                         70.57, 5.63,                                                                               10.04                                                                               70.4S,                                                                               5.71,                                                                               10.06                             I-8   C.sub.36 H.sub.31 N.sub.5 O.sub.5                                                         70.46, 5.09,                                                                               11.41                                                                               70.33,                                                                               5.20,                                                                               11.39                             I-9   C.sub.37 H.sub.33 N.sub.5 O.sub.5                                                         70.80, 5.30,                                                                               11.16                                                                               70.70,                                                                               5.44,                                                                               11.15                              I-10 C.sub.41 H.sub.41 N.sub.5 O.sub.5                                                         72.02, 6.04,                                                                               10.24                                                                               71.90,                                                                               6.15,                                                                               10.26                              I-11 C.sub.42 H.sub.43 N.sub.5 O.sub.5                                                         72.29, 6.21,                                                                               10.03                                                                               72.15,                                                                               6.35,                                                                               10.06                              I-12 C.sub.43 H.sub.45 N.sub.5 O.sub.5                                                         72.55, 6.37,                                                                               9.84 72.44,                                                                               6.48,                                                                               9.88                               I-13 C.sub.45 H.sub.49 N.sub.5 O.sub.5                                                         73.05, 6.67,                                                                               9.46 72.94,                                                                               6.78,                                                                               9.45                               I-14 C.sub.45 H.sub.49 N.sub.5 O.sub.5                                                         73.05, 6.67,                                                                               9.46 72.98,                                                                               6.77,                                                                               9.47                              ______________________________________                                    

EXAMPLE 10 Process A, Step (10) Synthesis of (S)-1-((2'-carboxybiphenyl-4-yl)methyl)-N,N-dimethyl-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[[4,5-c]pyridine-6-carboxamide (I-15)

Ten ml of ethyl alcohol and 20 ml of a 1N aqueous sodium hydroxide solution were added to (S)-1-((2'-cyanobiphenyl-4-yl) methyl)-N,N-dimethyl-5-diphenylacetyl-4,5,6, 7-tetrahydro-1H-imidazo-[4,5-c]pyridine-6-carboxamide (III-14) (1.9550 g, 0.00337 mol), and the mixture was refluxed under heating for 3 hours, then neutralized with a 6N hydrochloric acid solution, and concentrated. The residue was extracted with chloroform, washed with water, dried over sodium sulfate, and concentrated to obtain a light-yellow foamy material (2.1179 g). This material was purified by silica gel column chromatography (Kieselgel 60, 110 g, chloroform/methanol=50/1) to obtain the objective product (I-15; Compound No. 15) (1.8756 g; yield: 92.9%) as a white foamy material. MS (EI): 580 (M-18).

The compounds of Table 8, including compounds wherein R is 2-(1H-tetrazol-5-yl)phenyl, were synthesized in the similar way. The results of elementary analysis of the compounds of Table 8 are shown in Table 9.

                                      TABLE 8                                      __________________________________________________________________________     Compound                                                                       No.   R.sup.1                                                                           R.sup.2 '.                                                                         R.sup.3                                                                             R.sup.4                                                                           R.sup.   R.sup.7                                                                           R.sup.8                                                                           MS(EI)                                     __________________________________________________________________________     I-15  H  NMe.sub.2                                                                          CH(Ph).sub.2                                                                        H  2-carboxy-phenyl                                                                        H  H  580(M-18)                                  I-16  H  NMe.sub.2                                                                          CH(Ph).sub.2                                                                        H  2-(1H-tetrazol-                                                                         H  H  622(M+)                                                         5-yl)phenyl                                               I-17  nBu                                                                               NMe.sub.2                                                                          CH(Ph).sub.2                                                                        H  2-carboxy-phenyl                                                                        H  H  636(M-18)                                  I-18  nBu                                                                               NMe.sub.2                                                                          CH(Ph).sub.2                                                                        H  2-(1H-tetrazol-                                                                         H  H  678(M+)                                                         5-yl)phenyl                                               I-19  nBu                                                                               NMe.sub.2                                                                          Cfl (Ph) 2                                                                          Me 2-(IH-tetrazol-                                                                         H  H  692(M+)                                                         5-yl)phenyl                                               I-20  nBu                                                                               NMe.sub.2                                                                          CH(Ph).sub.2                                                                        Me 2-(1H-tetrazol-                                                                         Me Me 720(M+)                                                         5-yl)phenyl                                               __________________________________________________________________________

                  TABLE 9                                                          ______________________________________                                         Compound                                                                               Elementary Calcd. for   Found                                          No.     analysis   (C, H, N) (%)                                                                               (C, H, N) (%)                                  ______________________________________                                         I-15    C.sub.37 H.sub.34 N.sub.4 O.sub.4                                                         74.23, 5.72,                                                                               9.36 74.11,                                                                              5.80,                                                                               9.35                             I-16    C.sub.37 H.sub.34 N.sub.8 O.sub.2                                                         71.36, 5.50,                                                                               17.99                                                                               71.30,                                                                              5.55,                                                                               17.97                            I-17    C.sub.41 H.sub.42 N.sub.4 O.sub.4                                                         75.20, 6.46,                                                                               8.56 75.11,                                                                              6.50,                                                                               8.54                             I-18    C.sub.41 H.sub.42 N.sub.8 O.sub.2                                                         72.54, 6.23,                                                                               16.51                                                                               2.49,                                                                               6.30,                                                                               16.48                            I-19    C.sub.42 H.sub.44 N.sub.8 O.sub.2                                                         72.81, 6.40,                                                                               16.1 72.77,                                                                              6.49,                                                                               16.15                            I-20    C.sub.44 H.sub.48 N.sub.8 O.sub.2                                                         73.31, 6.71,                                                                               15.54                                                                               73.26,                                                                              6.78,                                                                               15.50                            ______________________________________                                    

EXAMPLE 11 Process B, Step (a) Synthesis of (S)-2-triphenylmethylamino-3-(1-triphenylmethylimidazol-5-yl)propanoic acid methyl ester (XXII)

Triethylamine (145 ml, 1.038 mol) was added to a solution of the compound (XXIII) (50.25 g, 0.208 mol) and TrCl (138.90 g, 0.498 mol) in CH₂ Cl₂ (500 ml) dropwise with stirring under ice cooling for 30 minutes, followed by 6-hour stirring at room temperature. The reaction mixture was poured into water and extracted with CH₂ Cl₂. The organic layer was washed with a saturated NaCl aqueous solution, dried over Na₂ SO₄, and concentrated to obtain a crude product (168.87 g) as a yellow oily material. This crude product was purified by silica gel column chromatography (hexane/acetone=3/1) to obtain the objective compound (XXII) (119.934 g; yield: 88.4%) as a white foamy material.

¹ H-NMR (CDCl₃) δ: 2.71 (d, 1H, J=10.5 Hz, NH), 2.78 (dd, 1H, J=6.9, 13.8 Hz), 2.96 (dd, 1H, J=6.9, 13.8 Hz), 3.05 (s, 3H), 3.66 (dt, 1H, J=6.9, 10.5 Hz), 6.62 (s, 1H), 7.11-7.15 (m, 9H), 7.18-7.21 (m, 6H), 7.26-7.32 (m, 9H), 7.36 (s, 1H), 7.43 (d-like, 6H, J=7.3 Hz).

IR (ν_(max), KBr): 3480, 1748, 1509, 1455, 1163, 748, 705 cm⁻¹.

EXAMPLE 12 Process B, Step (b) Synthesis of (S)-2-triphenylmethylamino-3-(1-triphenylmethylimidazol-5-yl) propanol (XXI)

The compound (XXII) (58.917 g, 0.0901 mol) was added to a suspension of LiAlH₄ (6.839 g, 0.180 mol) in dry Et₂ O (590 ml) over a period of 2.5 hours. The mixture was stirred under ice cooling for one hour, and then Na₂ SO₄ ·10H₂ O was added to the resulting solution to dispose of the excess LiAlH₄, followed by filtration with Celite 545. The filtrate was concentrated and the residue was diluted with CHCl₃, washed with a saturated NH₄ Cl aqueous solution and a saturated NaCl aqueous solution, then dried over Na₂ SO₄, and concentrated to obtain the objective compound (56.390 g; yield: 100%) as a white foamy material.

¹ H-NMR (CDCl₃) δ: 1.90 (b, 1H, NH), 1.95 (dd, 1H, J=6.4, 14.7 Hz), 2.38 (dd, 1H, J=3.2, 14.7 Hz), 2.91 (b, 1H), 2.99 (dd, 1H, J=6.4, 11.5 Hz), 3.47 (dd, 1H, J=3.2, 11.5 Hz), 4.95 (b, 1H, OH), 6.29 (s, 1H), 7.09-7.20 (m, 15H), 7.26-7.33 (m, 10H), 7.48-7.49 (m, 6H).

IR (ν_(max), KBr): 3480, 1550, 1455, 1036, 746, 702 cm⁻¹.

EXAMPLE 13 Process B, Step (c) Synthesis of (S)-1-t-butyldimethylsilyloxy-2-triphenylmethylamino-3-(1-triphenylmethylimidazol-5-yl)propane (xx)

Imidazole (12.269 g, 0.180 mol) and tert-butyldimethylsilyl chloride (TBDMSCl) (20.37 g, 0.135 mol) were added to a solution of the compound (XXI) (56.390 g, 0.0901 mol) in dry DMF (560 ml) under ice cooling, and the mixture was stirred at room temperature for 3.5 hours. The reaction mixture was poured into water, extracted with Et₂ O, washed with water and a saturated NaCl aqueous solution, then dried over Na₂ SO₄, and concentrated to obtain a light-yellow foamy material (67.602 g). This crude product was purified by silica gel column chromatography (hexane/acetone=5/1) to obtain the objective compound (XX) (58.770 g; yield: 88.1%) as a white foamy material.

¹ H-NMR (CDCl₃) δ: -0.13 (s, 6H), 0.80 (s, 9H), 1.60 (b, 1H, NH), 2.19 (dd, 1H, J=7.6, 14.2 Hz), 2.57 (dd, 1H, J=4.1, 14.2 Hz), 2.73 (b, 1H), 2.89 (dd, 1H, J=6.0, 9.6 Hz), 3.27 (dd, 1H, J=4.1, 9.6 Hz), 5.35 (s, 2H), 6.38 (s, 1H), 7.12-7.35 (m, 25H), 7.56 (d-like, 6H, J=7.3 Hz).

IR (ν_(max), KBr): 3100, 2990, 2970, 2925, 2890, 1508, 1480, 1455, 1253, 1132, 1090, 1072, 1035, 900, 830, 770, 742, 700, 658, 636 cm⁻¹.

EXAMPLE 14 Process B, Step (d) Synthesis of (S)-1-t-butyldimethylsilyloxy-2-triphenylmethylamino-3-(2-n-butyl-1-triphenylmethylimidazol-5-yl)propane (XIX-3)

A 1.5N nBuLi/hexane mixed solution (61.0 ml, 0.0914 mol) was added dropwise to a solution of the compound (XX) (22.557 g, 0.0305 mol) in dry Et₂ O (340 ml) over a period of 15 minutes by using an injector. Three minutes thereafter, nBuI (5.2 ml, 0.0457 mol) and HMPA (38 ml) were added dropwise with an injector under the same conditions. After 20-minute stirring, the mixture was heated to room temperature and further stirred for 4 hours. The reaction mixture was poured into water and extracted with EtOAc. The organic layer was washed with a saturated NaCl solution, then dried over Na₂ SO₄, and concentrated to obtain a yellow oily material (25.830 g; yield: 100% up). This material was purified by silica gel column chromatography (hexane/acetone=20/1) to obtain the objective compound (XIX-3) (10.710 g; yield: 44.1%) as a light-yellow foamy material.

¹ H-NMR (CD₂ Cl₂) δ: -0.136, -0.144 (each s, each 3H), 0.58 (t, 3H, J=7.3 Hz), 0.77 (s, 9H), 0.89 (sext, 2H, J=7.3 Hz), 1.01 (m, 1H), 1.12 (m, 1H), 1.78 (m, 2H), 1.98 (dd, 1H, J=6.7, 14.0 Hz), 2.43 (dd, 1H, J=4.8, 14.0 Hz), 2.57 (b, 1H, CH), 3.06 (dd, 1H, J=6.9, 9.6 Hz), 3.10 (b, 1H, NH), 3.28 (dd, 1H, J=4.4, 9.6 Hz), 6.19 (s, 1H), 7.06-7.54 (m, 30H).

IR (ν_(max), KBr): 3500, 3000, 2975, 2905, 1510, 1459, 1408, 1260, 1160, 1093, 1075, 1038, 834, 775, 746, 702, 640 cm⁻¹.

There were similarly synthesized the compounds of Table 10.

                                      TABLE 10                                     __________________________________________________________________________     Com-                                                                           pound  Elementary                                                                            Calcd. for    Found                                              No. R.sup.1                                                                           analysis                                                                              (C, H, N) (%) (C, H, N) (%)                                                                        MS(EI)                                       __________________________________________________________________________     XIX-1                                                                              nPr                                                                               C.sub.53 H.sub.59 N.sub.3 OSi                                                         81.39,                                                                             7.60,                                                                             5.37                                                                              81.50,                                                                             7.48,                                                                             5.30                                                                              782(M.sup.+)                                 XIX-2                                                                              iPr                                                                               C.sub.53 H.sub.59 N.sub.3 OSi                                                         81.39,                                                                             7.60,                                                                             5.37                                                                              81.47,                                                                             7.52,                                                                             5.29                                                                              782(M.sup.+)                                 XIX-3                                                                              nBu                                                                               C.sub.54 H.sub.61 N.sub.3 OSi                                                         81.46,                                                                             7.72,                                                                             5.28                                                                              81.61,                                                                             7.69,                                                                             5.19                                                                              796(M.sup.+)                                 XIX-4                                                                              nHex                                                                              C.sub.56 H.sub.65 N.sub.3 OSi                                                         82.61,                                                                             8.05,                                                                             5.16                                                                              82.76,                                                                             7.98,                                                                             5.09                                                                              814(M.sup.+)                                 __________________________________________________________________________

EXAMPLE 15 Process B, Step (e) Synthesis of (S)-2-amino-3-(2-n-butyl-1H-imidazol-5-yl)propanol (XVIII-3) and (S)-2-n-butyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-methanol hydrochloride (XVII-3)

A 1N HCl aqueous solution (140 ml) and a 37% HCHO aqueous solution (3.6 ml) were added to the compound (XIX-3) (11.745 g, 0.0148 mol) and the mixture was stirred first at room temperature for 40 minutes and then in a 120° C. oil bath for 4 hours. The reaction mixture was cooled and the insoluble portion was filtered out, followed by washing with water. The aqueous layer was washed with Et₂ O, then concentrated, and dried to obtain the objective compound (XVII-3) (4.0370 g; yield: 97.0%) as a yellow solid.

¹ H-NMR (D₂ O) δ: 0.95 (t, 3H, J=7.3 Hz), 1.40 (sext, 2H, J=7.3 Hz), 1.79 (quint, 2H, J=7.3 Hz), 3.02 (t, 2H, J=7.3 Hz), 3.12 (d-like, 1H, J=4.6 Hz), 3.16 (bs, 1H), 3.85-3.90 (m, 2H), 4.08 (d-like, 1H, J=9.2 Hz), 4.48 (d, 1H, J=15.4 Hz), 4.52 (d, 1H, J=15.4 Hz).

IR (ν_(max), KBr): 3410, 2950, 1675, 1620, 1560, 1430, 1065 cm⁻¹.

The compounds shown in Table 11 were similarly synthesized.

                  TABLE 11                                                         ______________________________________                                         Compound No.    R.sup.1                                                                               MS (EI)                                                 ______________________________________                                         XVII-1          nPr    195 (M-2HCl)                                            XVII-2          nhex   195 (M-2HCl)                                            XVII-3          nBu    209 (M-2HCl)                                            XVII-4          nhex   237 (M-2HCl)                                            ______________________________________                                    

By using the compound (XIX-3) (1.7750 g, 0.00223 mol) and an 1N HCl aqueous solution (18 ml), the above reaction procedure was followed without adding the 37% HCHO aqueous solution to obtain the objective compound (XVIII-3) (0.7003 g; yield: 99.6%) as a yellow viscous material.

¹ H-NMR (D₂ O) δ: 0.96 (t, 3H, J=7.3 Hz), 1.39 (sext, 2H, J=7.3 Hz), 1.80 (quint, 2H, J=7.3 Hz), 3.00 (t, 2H, J=7.3 Hz), 2.8-3.3 (m, 3H), 3.7-4.3 (m, 2H), 6.05 (bs, 1H).

MASS (EI): 197 (M-2HCl).

There were similarly synthesized the compounds shown in Table 12.

                  TABLE 12                                                         ______________________________________                                         Compound No.     R.sup.1                                                                               MASS (EI)                                              ______________________________________                                         XVIII-1          nPr    183 (M-2HCl)                                           XVIII-2          iPr    183 (M-2HCl)                                           XVIII-3          nBu    197 (M-2HCl)                                           XVIII-4          nHex   225 (M-2HCl)                                           ______________________________________                                    

EXAMPLE 16 Process B, Step (f) Synthesis of (S)-2-n-butyl-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-methanol (XVI-4)

Diphenylacetic acid (14.6617 g, 0.069 mol), N,N'-dicyclohexylcarbodiimide (DCCI) (14.2528 g, 0.069 mol), and 1-hydroxybenzotriazole (HBTA) (9.3345 g, 0.069 mol) were dissolved in dry THF (61 ml) and stirred at room temperature for 20 minutes. A solution of the compound (XVII-3) (6.0920 g, 0.0216 mol) in dry THF (30 ml) and dry triethylamine (TEA) (6.0 ml, 0.043 mol) were added to this solution, followed by stirring at room temperature for 14 hours. The insoluble portion was filtered out and washed with THF. The filtrate and washings were joined and concentrated to obtain a crude oily material (11.0015 g). This material was dissolved in a 1/1 mixture (100 ml) of THF and MeOH, after addition of a 1N HCl aqueous solution (25 ml), left as it was for 8 hours. Then, to the mixture added a 1/1 mixture (100 ml) of THF and MeOH and a 1N NaOH solution (50 ml), and the mixture was left as it was for 10 hours. The reaction mixture was concentrated. White crystals were precipitated by addition of H₂ O (50 ml). These crystals were washed with water and then vacuum dried to give the compound (XVI-4) (2.1518 g; m.p. 199°-202° C.; yield: 24.7%).

¹ H-NMR (CDCl₃) δ: 0.90, 0.91 (each t, 3H, J=7.3 Hz), 1.30-1.38 (m, 2H), 1.40-1.90 (b, 1H, OH), 1.55-1.70 (m, 2H), 2.55-2.62 (m, 2H), 2.33, 2.81 (s-like, dd, 2H), 3.43-3.58 (m, 2H), 3.86-4.08 (each d, 1H, J=16.7, 15.4 Hz), 4.47, 4.70 (bs, d, 2H, J=16.7 Hz), 5.28, 5.32, 5.51 (d, s, s, 2H, J=16.7 Hz), 7.10-7.60 (m, 10H), 8.80 (b, 1H, NH).

IR (ν_(max), KBr): 3425, 2970, 2930, 2860, 1620, 1450, 1420, 740, 695 cm⁻¹.

The compounds shown in Table 13 were similarly synthesized.

                                      TABLE 13                                     __________________________________________________________________________     Compound         Elementary                                                                            Calcd. for                                             No.   R.sup.1                                                                           R.sup.3 analysis                                                                              (C, H, N) (%)                                                                             Found (C, H, N) (%)                                                                       MS(EI)                           __________________________________________________________________________     XVI-1 H  (Ph).sub.2 CH                                                                          C.sub.21 H.sub.21 N.sub.3 O.sub.2                                                     72.76,                                                                             6.09,                                                                             12.09                                                                              72.78,                                                                             5.89,                                                                             12.00                                                                              347(M.sup.+)                     XVI-2 nPr                                                                               (Ph).sub.2 CH                                                                          C.sub.24 H.sub.27 N.sub.3 O.sub.2                                                     74.01,                                                                             6.99,                                                                             10.79                                                                              74.16,                                                                             6.83,                                                                             10.70                                                                              389(M.sup.+)                     XVI-3 iPr                                                                               (Ph).sub.2 CH                                                                          C.sub.24 H.sub.27 N.sub.3 O.sub.2                                                     74.01,                                                                             6.99,                                                                             10.79                                                                              74.21,                                                                             6.90,                                                                             10.69                                                                              389(M.sup.+)                     XVI-4 nBu                                                                               (Ph).sub.2 CH                                                                          C.sub.25 H.sub.29 N.sub.3 O.sub.2                                                     74.41,                                                                             7.24,                                                                             10.41                                                                              74.57,                                                                             7.20,                                                                             10.30                                                                              404(M.sup.+)                     XVI-5 nBu                                                                               (Ph)(c-Hex)CH                                                                          C.sub.25 H.sub.35 N.sub.3 O.sub.2                                                     73.31,                                                                             8.61,                                                                             10.26                                                                              73.49,                                                                             8.55,                                                                             10.19                                                                              410(M.sup.+)                     XVI-6 nHex                                                                              (Ph).sub.2 CH                                                                          C.sub.27 H.sub.33 N.sub.3 O.sub.2                                                     75.14,                                                                             7.71,                                                                              9.74                                                                              75.30,                                                                             7.68,                                                                              9.67                                                                              432(M.sup.+)                     __________________________________________________________________________

EXAMPLE 17 Process B, Step (g) Synthesis of (S)-2-n-butyl-1-[(4-methoxycarbonylphenyl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-methanol (XV-8)

Methyl 4-(bromomethyl)benzoate (0.0334 g, 0.00015 mol) and K₂ CO₃ (0.0201 g, 0.00015 mol) were added to a solution of the compound (XVI-4) (0.0491 g, 0.00012 mol) in dry DMF (0.49 ml), and the mixture was stirred vigorously at room temperature for 24 hours. The reaction mixture was poured into water, extracted with EtOAc, washed with water, then dried over Na₂ SO₄, and concentrated to obtain a light-yellow oily material (0.0656 g). This crude oily product was purified by silica gel column chromatography (hexane/acetone=1/2) to obtain the objective compound (XV-8) (0.0211 g), its 3-position isomer (0.0262 g), and a mixture of them (0.0035 g), each as a white foamy material (yield: 75.7%). The structures of the two compounds were determined by an NOE difference spectrum.

¹ H-NMR (CDCl₃) δ: 0.86, 0.87 (each, t, 3H, J=7.3 Hz), 1.28-1.36 (m, 2H), 1.58-1.65 (m, 3H, CH₃ CH₂ CH₂ CH₂ --, CH₂ OH), 1.99-2.63 (m, 2H), 2.52-2.63 (m, 2H), 3.31-3.57 (m, 2H, CH₂ OH), 3.92, 3.93 (each, s, 3H), 3.90, 4.13, 4.76, 5.42 (each, d, 2H, J=15.4 Hz), 4.40-4.47, 5.26-5.30 (each, m, 1H), 4.94, 5.02 (each, s, 2H), 5.35, 5.43 (each s, 1H), 6.91-6.99 (m, 2H), 7.17-7.32 (m, 10H), 7.98-8.01 (m, 2H).

IR (ν_(max), KBr): 3460, 1725, 1640, 1453, 1430, 1415, 1280, 1110, 743, 700 cm⁻¹.

EXAMPLE 18 Process B, Step (g) Synthesis of (S)-2-n-butyl-1-[(2'-cyanobiphenyl-4-yl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-methanol (XV-10)

4'-(bromomethyl)-2-cyanobiphenyl (2.3655 g, 0.0869 mol) and K₂ CO₃ (1.9222 g, 0.0139 mol) were added to a solution of the compound (XVI-4) (2.8060 g, 0.00695 mol) in dry DMF (28 ml), and the mixture was stirred vigorously at room temperature for 23 hours. The reaction mixture was poured into water, extracted with EtOAc, washed with water, dried over Na₂ SO₄, and concentrated to obtained a light-yellow foamy material (4.5301 g). This material was purified by silica gel column chromatography to obtain the compound (XV-10) (0.9288 g), its 3-position isomer (1.4733 g), and a mixture of them (0.0207 g) (yield: 58.6%). The structures of the two compounds were determined by an NOE difference spectrum.

¹ H-NMR (CDCl₃) δ: 0.89, 0.90 (each t, 3H, J=7.3 Hz), 1.36 (sext, 2H, J=7.3 Hz), 1.64-1.78 (m, 2H), 1.88 (bs, 1H, OH), 2.14, 2.72 (each dd, 1H, J=6.0, 15.6 Hz), 2.21, 2.51 (each d, 1H, J=15.6 Hz), 2.60-2.67 (m, 2H), 3.35-3.62 (m, 2H, CH₂ OH), 3.96, 4.93 (each d, 1H, J=17.0 Hz), 4.12, 4.78 (each d, 1H, J=15.6 Hz), 4.47-4.51, 5.35-5.40 (each m, 1H), 5.06-5.13 (m, 2H), 5.36, 5.42 (each s, 1H), 6.93-7.10 (m, 2H), 7.15-7.39 (m, 10H), 7.40-7.58 (m, 4H), 7.60-7.82 (m, 2H).

IR (ν_(max), KBr): 3425, 2960, 2925, 2860, 1637, 1500, 1480, 1450, 1410, 1375, 760, 740, 700 cm⁻¹.

There were similarly synthesized the compounds shown in Table 14.

                                      TABLE 14                                     __________________________________________________________________________     Compound                     Elementary                                                                            Calcd. for                                 No.   R.sup.1                                                                           R.sup.3                                                                             R.sup.4                                                                           R.sup.7                                                                           R.sup.8                                                                           R.sup.6                                                                              analysis                                                                              (C, H, N) (%)                                                                             Found (C, H, N)                                                                           MS(EI)               __________________________________________________________________________     XV-1  H  (Ph).sub.2 CH                                                                       H  H  H  COOMe C.sub.30 H.sub.29 N.sub.3 O.sub.4                                                     72.71,                                                                             5.90,                                                                             8.48                                                                               72.90,                                                                             5.79,                                                                             8.40                                                                               496(M.sup.+)         XV-2  H  (Ph).sub.2 CH                                                                       H  Me Me COOMe C.sub.32 H.sub.33 N.sub.3 O.sub.4                                                     73.40,                                                                             6.35,                                                                             8.02                                                                               73.51,                                                                             6.30,                                                                             7.99                                                                               524(M.sup.+)         XV-3  H  (Ph).sub.2 CH                                                                       Me H  H  NO.sub.2                                                                             C.sub.29 H.sub.28 N.sub.4 O.sub.4                                                     70.15,                                                                             5.68,                                                                             11.28                                                                              70.30,                                                                             5.60,                                                                             11.22                                                                              497(M.sup.+)         XV-4  H  (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.35 H.sub.30 N.sub.4 O.sub.2                                                     78.04,                                                                             5.61,                                                                             10.40                                                                              78.20,                                                                             5.54,                                                                             10.33                                                                              539(M.sup.+)         XV-5  H  (Ph).sub.2 CH                                                                       H  H  H  2-(1-Tr-1H-                                                                          C.sub.54 H.sub.45 N.sub.7 O.sub.2                                                     78.71,                                                                             5.50,                                                                             11.90                                                                              78.89,                                                                             5.40,                                                                             11.83                                                                              824(M.sup. +)                               tetrazol-5-                                                                    yl)Ph                                                   XV-6  nPr                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.38 H.sub.36 N.sub.4 O.sub.2                                                     78.59,                                                                             6.25,                                                                             9.65                                                                               78.71,                                                                             6.19,                                                                             9.58                                                                               581(M.sup.+)         XV-7  iPr                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.38 H.sub.36 N.sub.4 O.sub.2                                                     78.59,                                                                             6.25,                                                                             9.65                                                                               78.66,                                                                             6.21,                                                                             9.63                                                                               581(M.sup.+)         XV-8  nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  COOMe C.sub.34 H.sub.37 N.sub.3 O.sub.4                                                     74.02,                                                                             6.76,                                                                             7.62                                                                               74.21,                                                                             6.66,                                                                             7.59                                                                               552(M.sup.+)         XV-9  nBu                                                                               (Ph).sub.2 CH                                                                       Me H  H  NO.sub.2                                                                             C.sub.34 H.sub.38 N.sub.4 O.sub.4                                                     72.06,                                                                             6.76,                                                                             9.89                                                                               72.25,                                                                             6.64,                                                                             9.78                                                                               567(M.sup.+)         XV-10 nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.39 H.sub.38 N.sub.4 O.sub.2                                                     78.76,                                                                             6.44,                                                                             9.42                                                                               78.91,                                                                             6.38,                                                                             9.39                                                                               595(M.sup.+)         XV-11 nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-(1-Tr-1H-                                                                          C.sub.58 H.sub.53 N.sub.7 O.sub.2                                                     79.15,                                                                             6.07,                                                                             11.14                                                                              79.30,                                                                             5.98,                                                                             11.07                                                                              880(M.sup.+)                                tetrazol-5-                                                                    yl)Ph                                                   XV-12 nBu                                                                               (Ph)(c-                                                                             H  H  H  2-CN-Ph                                                                              C.sub.39 H.sub.44 N.sub.4 O.sub.2                                                     77.97,                                                                             7.38,                                                                             9.33                                                                               78.10,                                                                             7.29,                                                                             9.30                                                                               601(M.sup.+)                  Hex)CH                                                                XV-13 nHex                                                                              (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.41 H.sub.42 N.sub.4 O.sub.2                                                     79.07,                                                                             6.80,                                                                             9.00                                                                               79.22,                                                                             6.77,                                                                             8.95                                                                               623(M.sup.+)         __________________________________________________________________________

EXAMPLE 19 Process B, Step (h) Synthesis of (S)-2-n-butyl-1-[(4-methoxycarbonylphenyl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo [4,5-c]pyridine-6-carboxylic acid (XIV-8)

CrO₃ (0.33 g) was dissolved in H₂ O (0.62 ml), and concentrated H₂ SO₄ was slowly added dropwise thereto. The resultantly produced salt was dissolved in H₂ O (0.1 ml) to prepare an oxidizing reagent. Meanwhile, the compound (XV-8) (0.2916 g) was dissolved in acetone (4.4 ml), and the previously prepared oxidizing reagent was added dropwise thereto at room temperature until the orangish red color did not fade away. After 30-minute stirring, iPrOH was added to the reaction mixture until it assumed a green color, and then the mixture was concentrated. The resulting crude product was purified by silica gel column chromatography (CHCl₃ /MeOH=8/1) to obtain the objective compound (XIV-8) (0.1883 g; m.p. 177°-180° C.; yield: 63.0%).

¹ H-NMR (CDCl₃) δ: 0.79, 0.83 (each t, 3H, J=7.3 Hz), 1.18-1.28 (m, 2H), 1.40-1.55 (m, 2H), 1.77, 2.99, 3.24-3.44 (m, d, m, 2H, J=14.7 Hz), 2.45-2.70 (m, 2H), 3.89, 3.92 (each s, 3H), 4.28, 4.57, 4.69, 5.07 (each d, 2H, J=14.7 Hz), 5.17-5.27 (m, 2H), 5.51, 5.55 (each s, 1H), 5.51-5.55, 5.70 (d, 1H, J=5.5 Hz), 7.09-7.45 (m, 12H), 7.90-8.10 (m, 2H).

IR (ν_(max), KBr): 3470, 2980, 1726, 1640, 1615, 1506, 1455, 1435, 1417, 1283, 1190, 1112, 750, 700 cm⁻¹.

EXAMPLE 20 Process B, Step (h) Synthesis of (S)-2-n-butyl-1-[(2'-cyanobiphenyl-4-yl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid (XIV-10)

The oxidizing reagent (0.9 ml) as prepared in Example 19 was added dropwise to a solution of the compound (XV-10) (0.6249 g, 0.00105 mol) in acetone (9.4 ml) at room temperature. After 30-minute stirring, iPrOH was added to the reaction mixture until it assumed a green color, and then the mixture was concentrated. The resulting crude product was purified by silica gel column chromatography (CHCl₃ /MeOH=6/1) to obtain the compound (XIV-10) (0.3619 g; yield: 56.6%) as a white foamy material.

¹ H-NMR (CDCl₃) δ: 0.75-1.06 (m, 3H), 1.15-1.40 (m, 2H), 1.44-1.70 (m, 2H), 2.46-2.64 (m, 2H), 2.69, 2.93 (each dd, 1H, J=6.0, 15.6 Hz), 3.08, 3.31 (each d, 1H, J=15.6 Hz), 4.27, 4.67 (each d, 1H, J=15.6 Hz), 4.58, 4.99 (each d, 1H, J=15.6 Hz), 4.94-5.25 (m, 2H), 5.32, 5.43 (each s, 1H), 4.83, 5.68 (each d, 1H, J=6.0 Hz), 7.02-7.85 (m, 18H).

IR (ν_(max), KBr) ν_(max) : 3425, 2960, 1620, 1500, 1408, 758, 742, 700, 630, 560 cm⁻¹.

There were similarly synthesized the compounds shown in Table 15.

                                      TABLE 15                                     __________________________________________________________________________     Compound                     Elementary                                                                            Calcd. for            MS                   No.   R.sup.1                                                                           R.sup.3                                                                             R.sup.4                                                                           R.sup.7                                                                           R.sup.8                                                                           R.sup.6                                                                              analysis                                                                              (C, H, N) (%)                                                                             Found (C, H, N)                                                                           (FAB)                __________________________________________________________________________     XIV-1 H  (Ph).sub.2 CH                                                                       H  H  H  COOMe C.sub.30 H.sub.27 N.sub.3 O.sub.5                                                     70.71,                                                                             5.34,                                                                             8.25                                                                               70.89,                                                                             5.29,                                                                             8.18                                                                               510(M.sup.+)         XIV-2 H  (Ph).sub.2 CH                                                                       H  Me Me COOMe C.sub.32 H.sub.31 N.sub.3 O.sub.5                                                     71.49,                                                                             5.81,                                                                             7.82                                                                               71.63,                                                                             5.77,                                                                             7.74                                                                               538(M.sup.+)         XIV-3 H  (Ph).sub.2 CH                                                                       Me H  H  NO.sub.2                                                                             C.sub.29 H.sub.26 N.sub.4 O.sub.5                                                     68.22,                                                                             5.13,                                                                             10.97                                                                              68.40,                                                                             5.09,                                                                             10.88                                                                              511(M.sup.+)         XIV-4 H  (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.35 H.sub.28 N.sub.4 O.sub.3                                                     76.07,                                                                             5.11,                                                                             10.14                                                                              76.21,                                                                             5.04,                                                                             10.07                                                                              553(M.sup.+)         XIV-5 H  (Ph).sub.2 CH                                                                       H  H  H  2-(1-Tr-1H-                                                                          C.sub.54 H.sub.43 N.sub.7 O.sub.3                                                     77.40,                                                                             5.17,                                                                             11.70                                                                              77.55,                                                                             5.09,                                                                             11.65                                                                              838(M.sup. +)                               tetrazol-5-                                                                    yl)Ph                                                   XIV-6 nPr                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.38 H.sub.34 N.sub.4 O.sub.3                                                     76.75,                                                                             5.76,                                                                             9.42                                                                               76.91,                                                                             5.65,                                                                             9.38                                                                               595(M.sup.+)         XIV-7 iPr                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.38 H.sub.34 N.sub.4 O.sub.3                                                     76.75,                                                                             5.76,                                                                             9.42                                                                               76.88,                                                                             5.59,                                                                             9.40                                                                               595(M.sup.+)         XIV-8 nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  COOMe C.sub.34 H.sub.35 N.sub.3 O.sub.5                                                     72.19,                                                                             6.24,                                                                             7.43                                                                               72.30,                                                                             6.20,                                                                             7.38                                                                               566(M.sup.+)         XIV-9 nBu                                                                               (Ph).sub.2 CH                                                                       Me H  H  NO.sub.2                                                                             C.sub.34 H.sub.36 N.sub.4 O.sub.5                                                     70.33,                                                                             6.25,                                                                             9.65                                                                               70.50,                                                                             6.19,                                                                             9.62                                                                               581(M.sup.+)         XIV-10                                                                               nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.39 H.sub.36 N.sub.4 O.sub.3                                                     76.95,                                                                             5.96,                                                                             9.20                                                                               77.09,                                                                             5.88,                                                                             9.14                                                                               609(M.sup.+)         XIV-11                                                                               nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-(1-Tr-1H-                                                                          C.sub.58 H.sub.51 N.sub.7 O.sub.3                                                     77.92,                                                                             5.75,                                                                             10.97                                                                              80.10,                                                                             5.64,                                                                             10.85                                                                              894(M.sup.+)                                tetrazol-5-                                                                    yl)Ph                                                   XIV-12                                                                               nBu                                                                               (Ph)(c-                                                                             H  H  H  2-CN-Ph                                                                              C.sub.39 H.sub.42 N.sub.4 O.sub.3                                                     76.19,                                                                             6.89,                                                                             9.11                                                                               76.33,                                                                             6.75,                                                                             9.08                                                                               615(M.sup.+)                  Hex)CH                                                                XIV-13                                                                               nHex                                                                              (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                              C.sub.41 H.sub.40 N.sub.4 O.sub.3                                                     77.33,                                                                             6.33,                                                                             8.80                                                                               77.21,                                                                             6.54,                                                                             8.65                                                                               637(M.sup.+)         __________________________________________________________________________

EXAMPLE 21 Process B, Step (i) Synthesis of 4-[[(S)-2-butyl-1-[(4-methoxycarbonylphenyl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (XIII-8)

The compound (XIV-8) (0.1315 g, 0.00023 mol), DCCI (0.0624 g, 0.0003 mol), HBTA (0.0377 g, 0.00028 mol), and morpholine (0.024 ml, 0.00028 mol) were dissolved in dry THF (2.0 ml) and stirred at room temperature for 19 hours. The insoluble portion was filtered out and washed with THF. The filtrate and washings were joined and concentrated to obtain a crude oily product (0.3010 g). This crude product was purified by silica gel column chromatography (CHCl₃ /MeOH=60/1) to obtain a white foamy material (0.1204 g). This material was again purified by using a preparative TLC plate (0.5 mm thick, 20 cm×20 cm; developing solvent: hexane/acetone=2/3) to obtain the objective compound (XIII-8) (0.0911 g; yield: 61.7%).

¹ H-NMR (CDCl₃) δ: 0.84 (t, 3H, J=7.3 Hz), 1.28 (sext, 2H, J=7.3 Hz), 1.58 (quint, 2H, J=7.3 Hz), 2.49 (t, 2H, J=7.3 Hz), 2.70 (dd, 1H, J=6.0, 15.1 Hz), 2.80 (d, 1H, J=15.1 Hz), 3.25-3.70 (b, 8H), 3.92 (s, 3H), 4.26 (d, 1H, J=15.1 Hz), 4.90 (d, 1H, J=15.1 Hz), 5.02, 5.07 (each d, each 1H, J=17.4 Hz), 5.35 (s, 1H), 5.96 (d, 1H, J=6.0 Hz), 7.09 (d, 2H, J=8.3 Hz), 7.17-7.35 (m, 10H), 8.02 (d, 2H, J=8.3 Hz).

IR (ν_(max), KBr): 3460, 1725, 1645, 1455, 1433, 1415, 1280, 1230, 1113, 750, 700 cm⁻¹.

EXAMPLE 22 Process B, Step (i) Synthesis of 4-[[(S)-2-butyl-1-[(2'-cyanobiphenyl-4-yl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (XIII-10)

The compound (XIV-10) (0.3301 g, 0.000542 mol), DCCI (0.1455 g, 0.000705 mol), HBTA (0.0953 g, 0.000705 mol), and morpholine (0.06 ml, 0.000705 mol) were dissolved in dry THF (5.0 ml) and stirred at room temperature for 48 hours. The insoluble portion was filtered out and washed with THF. The filtrate and washings were joined and concentrated to obtain a crude product (0.5500 g). This crude product was purified by silica gel column chromatography (hexane/acetone=2/3) to obtain the objective compound (XIII-10) (0.1764 g; yield: 48.0%) as a white foamy material.

¹ H-NMR (CDCl₃) δ: 0.87 (t, 3H, J=7.3 Hz), 1.32 (sext, 2H, J=7.3 Hz), 1.64 (quint, 2H, J=7.3 Hz), 2.55 (t, 2H, J=7.3 Hz), 2.77 (dd, 1H, J=6.0, 15.1 Hz), 2.86 (d, 1H, J=15.1 Hz), 3.20-3.80 (b, 8H), 4.29 (d, 1H, J=15.6 Hz), 4.90 (d, 1H, J=15.6 Hz), 5.04 (d, 1H, J=17.0 Hz), 5.09 (d, 1H, J=17.0 Hz), 5.37 (s, 1H), 5.99 (d, 1H, J=6.0 Hz), 7.20-7.85 (m, 18H).

IR (ν_(max), KBr): 3430, 1640, 1450, 1408, 1228, 1113, 760, 700 cm⁻¹.

MS (EI): 678 (M⁺):

The compounds shown in Tables 16 and 17 were similarly synthesized.

                                      TABLE 16                                     __________________________________________________________________________     Com-                                                                           pound                             Elementary                                                                            Calcd. for                                                                              Found    MS                  No. R.sup.1                                                                           R.sup.3                                                                             R.sup.4                                                                           R.sup.7                                                                           R.sup.8                                                                           R.sup.6                                                                              R.sup.2 '                                                                             analysis                                                                              (C, H, N) (%)                                                                           (C, H, N)                                                                               (EI)                __________________________________________________________________________     XIII- 1                                                                            H  (Ph).sub.2 CH                                                                       H  H  H  COOMe                                                                                 ##STR12##                                                                            C.sub.34 H.sub.34 N.sub.4 O.sub.5                                                     70.57, 5.92, 9.68                                                                       70.70, 5.88,                                                                            579 (M.sup.+)       XIII- 2                                                                            H  (Ph).sub.2 CH                                                                       H  Me Me COOMe                                                                                 ##STR13##                                                                            C.sub.36 H.sub.38 N.sub.4 O.sub.5                                                     71.27, 6.31, 9.23                                                                       71.43, 6.18,                                                                            607 (M.sup.+)       XIII- 3                                                                            H  (Ph).sub.2 CH                                                                       Me H  H  NO.sub.2                                                                              ##STR14##                                                                            C.sub.33 H.sub.33 N.sub.5 O.sub.5                                                     68.38, 5.74, 12.08                                                                      68.51, 5.65,                                                                            580 (M.sup.+)       XIII- 4                                                                            H  (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                               ##STR15##                                                                            C.sub.39 H.sub.35 N.sub.5 O.sub.3                                                     75.34, 5.67, 11.26                                                                      75.51, 5.59,                                                                            622 (M.sup.+)       XIII- 5                                                                            H  (Ph).sub.2 CH                                                                       H  H  H  2-(1-Tr-1H- tetrazol-5- yl)Ph                                                         ##STR16##                                                                            C.sub.58 H.sub.50 N.sub.8 O.sub.3                                                     76.80, 5.56, 12.35                                                                      76.96, 5.49,                                                                            907 (M.sup.+)       XIII- 6                                                                            nPr                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                               ##STR17##                                                                            C.sub.42 H.sub.41 N.sub.5 O.sub.3                                                     75.99, 6.23, 10.55                                                                      76.10, 6.19,                                                                            664 (M.sup.+)       XIII- 7                                                                            iPr                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                               ##STR18##                                                                            C.sub.42 H.sub.41 N.sub.5 O.sub.3                                                     75.99, 6.23, 10.55                                                                      76.15, 6.16,                                                                            664 (M.sup.+)       XIII- 8                                                                            nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  COOMe                                                                                 ##STR19##                                                                            C.sub.38 H.sub.42 N.sub.4 O.sub.5                                                     71.90, 6.67, 8.83                                                                       72.05, 6.58,                                                                            635 (M.sup.+)       XIII- 9                                                                            nBu                                                                               (Ph).sub.2 CH                                                                       Me H  H  NO.sub.2                                                                              ##STR20##                                                                            C.sub.37 H.sub.41 N.sub.5 O.sub.5                                                     69.90, 6.50, 11.02                                                                      70.09, 6.44,                                                                            636 (M.sup.+)       XIII- 10                                                                           nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                               ##STR21##                                                                            C.sub.43 H.sub.43 N.sub.5 O.sub.3                                                     76.19, 6.39, 10.33                                                                      76.31, 6.28,                                                                            678 (M.sup.+)       XIII- 11                                                                           nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-(1-Tr-1H- tetrazol-5- yl)Ph                                                         ##STR22##                                                                            C.sub. 62 H.sub.58 N.sub.8 O.sub.3                                                    77.31, 6.07, 11.63                                                                      77.49, 5.95,                                                                            963 (M.sup.+)       XIII- 12                                                                           nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                               ##STR23##                                                                            C.sub.43 H.sub.43 N.sub.5 O.sub.2                                                     74.43, 6.25, 10.09                                                                      74.56, 6.21,                                                                            694 (M.sup.+)       XIII- 13                                                                           nBu                                                                               (Ph).sub.2 CH                                                                       H  H  H  2-CN-Ph                                                                               ##STR24##                                                                            C.sub.43 H.sub.44 N.sub.6 O.sub.2                                                     76.30, 6.55, 12.42                                                                      76.48, 6.50,                                                                            677 (M.sup.+)       __________________________________________________________________________

                                      TABLE 17                                     __________________________________________________________________________     Compound                         Elementary                                                                            Calcd. for                                                                              Found                         No.   R.sup.1                                                                           R.sup.3                                                                             R.sup.4                                                                          R.sup.7                                                                           R.sup.8                                                                          R.sup.6                                                                             R.sup.2 '                                                                             analysis                                                                              (C, H, N) (%)                                                                           (C, H, N)                                                                               MS(EI)               __________________________________________________________________________     XIII-14                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                              ##STR25##                                                                            C.sub.42 H.sub.41 N.sub.5 O.sub.2                                                     77.87, 6.38, 10.81                                                                      78.01, 6.29,                                                                            648(M.sup.+)         XIII-15                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                              ##STR26##                                                                            C.sub.43 H.sub.43 N.sub.5 O.sub.2                                                     78.03, 6.55, 10.58                                                                      78.18, 6.48,                                                                            662(M.sup.+)         XIII-16                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                              ##STR27##                                                                            C.sub.44 H.sub.45 N.sub.5 O.sub.2                                                     78.19, 6.71, 10.36                                                                      78.33, 6.64,                                                                            676(M.sup.+)         XIII-17                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                             NH.sub.2                                                                              C.sub.39 H.sub.37 N.sub.5 O.sub.2                                                     77.08, 6.14, 11.52                                                                      77.22, 6.05,                                                                            608(M.sup.+)         XIII-18                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                             NHME   C.sub.40 H.sub.39 N.sub.5 O.sub.2                                                     77.27, 6.32, 11.26                                                                      77.42, 6.28,                                                                            622(M.sup.+)         XIII-19                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                             N(Me).sub.2                                                                           C.sub.41 H.sub.41 N.sub.5 O.sub.2                                                     77.45, 6.50, 11.02                                                                      77.61, 6.38,                                                                            636(M.sup.+)         XIII-20                                                                              nBu                                                                               (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                             N(Et).sub.2                                                                           C.sub.43 H.sub.45 N.sub.5 O.sub.2                                                     77.80, 6.83, 10.55                                                                      77.96, 6.74,                                                                            664(M.sup.+)         XIII-21                                                                              nBu                                                                               (Ph)(c- Hex)CH                                                                      H H  H 2-CN-Ph                                                                              ##STR28##                                                                            C.sub.43 H.sub.49 N.sub.5 O.sub.3                                                     75.52, 7.22, 10.24                                                                      75.71, 7.14,                                                                            684(M.sup.+)         XIII-22                                                                              nHex                                                                              (Ph).sub.2 CH                                                                       H H  H 2-CN-Ph                                                                              ##STR29##                                                                            C.sub.45 H.sub.47 N.sub.5 O.sub.3                                                     76.57, 6.71, 9.92                                                                       76.71, 6.58,                                                                            706(M.sup.+)         __________________________________________________________________________

EXAMPLE 23 Process B, Step (j) Synthesis of 4-[[(S)-2-n-butyl-1-[(4-carboxyphenyl)methyl]5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (I-29)

The compound (XIII-8) (0.0761 g, 0.00012 mol) was dissolved in a 1/1 mixture of THF and MeOH (1.52 ml), followed by addition of a 1N NaOH aqueous solution (0.38 ml), and the mixture was left as it was for 16.5 hours. The reaction mixture was concentrated, and a 1N HCl aqueous solution (0.43 ml) (pH 4) was added thereto to cause acid precipitation. The resulting oily material was dissolved in CHCl₃, washed with water, dried over Na₂ SO₄, and concentrated to obtain the objective compound (I-29) (0.0735 g; yield: 98.8%) as a white foamy material.

¹ H-NMR (CDCl₃ +D₂ O) δ: 0.84 (t, 3H, J=7.3 Hz), 1.27 (sext, 2H, J=7.3 Hz), 1.57 (quint, 2H, J=7.3 Hz), 2.55 (t, 2H, J=7.3 Hz), 2.70 (dd, 1H, J=6.0, 15.6 Hz), 2.86 (d, 1H, J=15.6 Hz), 3.30-3.65 (b, 8H), 4.24 (d, 1H, J=15.6 Hz), 5.06 (d, 1H, J=17.4 Hz), 5.10 (d, 1H, J=17.4 Hz), 5.12 (d, 1H, J=15.6 Hz), 5.43 (s, 1H), 5.97 (d, 1H, J=6.0 Hz), 7.12 (d, 2H, J=8.3 Hz), 7.17-7.33 (m, 10H), 8.09 (d, 2H, J=8.3 Hz).

IR (ν_(max), KBr): 3460, 1715, 1646, 1453, 1412, 1270, 1230, 1115, 745, 700 cm⁻¹.

EXAMPLE 24 Process B, Step (k) Synthesis of 4-[[(S)-1-[(4-amino-3-methylphenyl)methyl]-5-diphenytacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (I'-1)

The compound (XIII-3) (1.0079 g, 0.00174 mol) was dissolved in 10 ml of ethyl acetate, then tin chloride dihydrate (1.9632 g, 0.00870 mol) was added thereto. The mixture was stirred on an 80° C. oil bath in a stream of nitrogen for 30 minutes. The reaction mixture was cooled, neutralized with a 5% sodium carbonate aqueous solution, and concentrated. The residue was extracted with chloroform. The chloroform layer was washed with water, dried over anhydrous sodium sulfate, and concentrated to obtain a light-yellow foamy material. This substance was purified by silica gel column chromatography (chloroform/methanol=70/1) to obtain the objective compound (I'-1) (0.8781 g; yield: 91.9%) as a white foamy material.

¹ H-NMR (CDCl₃) δ: 2.10 (s, 3H), 2.74 (dd, 1H, J=6.4, 15.6 Hz), 3.20 (d, 1H, J=15.6 Hz), 3.2-3.8 (b, 10H), 4.29 (d, 1H, J=14.8 Hz), 4.75 (d, 1H, J=14.8 Hz), 4.80 (d, 1H, J=15.0 Hz), 4.90 (d, 1H, J=15.0 Hz), 5.35 (s, 1H), 6.01 (d, 1H, J=6.4 Hz), 6.62 (d, 1H, J=8.3 HZ), 6.80 (d, 1H, J=8.3 Hz), 6.81 (s, 1H), 7.1-7.4 (m, 11H).

MS (EI): 550 (M⁺).

Elementary analysis Calcd. for C₃₃ H₃₅ N₅ O₃ (%): C, 72.11; H, 6.42; N, 12.74. Found: C, 72.21; H, 6.35; N, 12.66.

EXAMPLE 25 Process B, Step (l) Synthesis of 4-[[(S)-2-n-butyl-5-diphenylacetyl-1-[(2'-1H-tetrazol-5-yl)biphenyl-4-yl) methyl]-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (I-31)

Trimethyltin azide (0.0998 g, 0.000485 mol) was added to a solution of the compound (XIII-10) (0.1644 g, 0.000243 mol) in o-xylene (2.5 ml), and the mixture was stirred on a 120° C. oil bath in a nitrogen stream for 90 hours. The reaction mixture was cooled. The insoluble portion was filtered out, washed with hot toluene, and vacuum dried. The resulting light-yellow solid was dissolved in MeOH (1.8 ml), and a 1N HCl aqueous solution (0.9 ml) was added thereto, and the mixture was stirred at room temperature for 15 minutes. The reaction mixture was adjusted to pH 4 by adding a 1N NaOH aqueous solution and then concentrated, and the residue was extracted with CHCl₃. The chloroform layer was washed with water, dried over anhydrous sodium sulfate, and concentrated to obtain a light-yellow foamy material. This material was purified by silica gel column chromatography (chloroform/methanol=10/1) to obtain the objective compound (I-31) (0.1281 g; yield: 73.3%) as a white foamy material.

¹ H-NMR (CDCl₃ +D₂ O) δ: 0.92 (t, 3H, J=7.3 Hz), 1.35 (sext, 2H, J=7.3 Hz), 1.52-1.73 (m, 2H), 1.38-2.75 (m, 4H), 3.20-3.67 (m, 8H), 3.76 (d, 1H, J=15.1 Hz), 4.54 (d, 1H, J=15.1 Hz), 4.92 (d, 1H, J=16.5 Hz), 5.05 (d, 1H, J=16.5 Hz), 5.14 (s, 1H), 5.81 (bs, 1H), 6.92-7.96 (m, 18H).

IR (ν_(max), KBr): 3425, 1635, 1445, 1405, 1225, 1108, 748, 700 cm⁻¹.

MS (FAB): 721 (M⁺).

EXAMPLE 26 Process B, Step (m) Synthesis of 4-[[(S)-5-diphenylacetyl-1-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl)methyl]-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (I-24)

A 12% HCl aqueous solution (5.5 ml) was added to a solution of the compound (XIII-5) (1.1103 g, 0.00122 mol) in THF (11 ml), and the mixture was stirred at room temperature for 4 hours. The reaction solution was neutralized by adding a 10% NaOH aqueous solution and concentrated. The residue was dissolved in a 1N NaOH aqueous solution and the insoluble portion was filtered out. The filtrate was adjusted to pH 4 by adding a 1N HCl aqueous solution and extracted with CHCl₃. The chloroform layer was washed with water, dried over anhydrous sodium sulfate, and concentrated to obtain a light-yellow foamy material. This material was purified by silica gel column chromatography (chloroform/methanol=10/1) to obtain the objective compound (I-24) (0.7413 g; yield: 91.1%) as a white foamy material.

¹ H-NMR (D₂ O+NaOD) δ: 2.71 (dd, 1H, J=7.2 Hz), 2.80 (d, 1H, J=15.1 Hz), 3.2-3.8 (b, 8H), 4.27 (d, 1H, J=15.1 Hz), 5.85 (b, 1H), 6.8-8.1 (m, 19H).

MASS (FAB): 665 (M⁺)

Elementary analysis Calcd. for C₃₉ H₃₆ N₈ O₃ (%): C, 70.46; H, 5.46; N, 16.86. Found: C, 70.55; H, 5.40; N, 16.71.

EXAMPLE 27 Process B, Step (n) Synthesis of 4-[[(S)-1-[[4-(2-carboxybenzamido)-3-methyl]phenyl]methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridin-6-yl]carbonyl]morpholine (1-23)

A solution of phthalic anhydride (0.3236 g, 0.00219 mol) in ethyl acetate (3.3 ml) was added to a solution of the compound (I'-1) (0.8007 g, 0.00146 mol) in ethyl acetate (12 ml) with stirring at room temperature, and the mixture was stirred for 23 hours. The reaction mixture was filtered, and the resulting white solid was washed with ethyl acetate and dried to obtain the objective compound (I-23) (0.8691 g; m.p. 191°-196° C.; yield: 85.5%).

¹ H-NMR (D₂ O+NaOD) δ: 2.24 (s, 3H), 2.30, 2.75 (each dd, 1H, J=5.6, 16.1 Hz), 2.95, 3.11 (each, d, 1H, J=16.1 Hz), 3.2-3.8 (b, 8H), 3.9-4.1 (m, 1H), 5.70 (b, 1H), 6.9-8.0 (m, 17H), 9.7 (b, 1H).

MASS (FAB): 698 (M⁺).

Elementary analysis Calcd. for C₄₁ H₃₉ N₅ O₆ (%): C, 70.57; H, 5.63; N, 10.04. Found: C, 70.79; H, 5.48; N, 10.01.

The compounds shown in Tables 18 and 19 were synthesized in the similar way.

                                      TABLE 18                                     __________________________________________________________________________     Com-                                                                           pound                             Elementary                                                                            Calcd. for                                                                              Found    MS                  No. R.sup.1                                                                           R.sup.2 R.sup.3                                                                             R.sup.4                                                                           R    R.sup.7                                                                           R.sup.8                                                                           analysis                                                                              (C, H, N) (%)                                                                           (C, H, N)                                                                               (FAB)               __________________________________________________________________________     I-21                                                                               H                                                                                  ##STR30##                                                                             (Ph).sub.2 CH                                                                       H  COOH H  H  C.sub.33 H.sub.32 N.sub.4 O.sub.5                                                     70.20, 5.71, 9.92                                                                       70.39, 5.65,                                                                            565, M.sup.+        I-22                                                                               H                                                                                  ##STR31##                                                                             (Ph).sub.2 CH                                                                       H  COOH Me Me C.sub.35 H.sub.36 N.sub.4 O.sub.5                                                     70.93, 6.12, 9.45                                                                       80.05, 6.08,                                                                            593, M.sup.+        I-23                                                                               H                                                                                  ##STR32##                                                                             (Ph).sub.2 CH                                                                       Me NHCO (2- COOH-  Ph)                                                                 H  H  C.sub.41 H.sub.39 N.sub.5 O.sub.6                                                     70.57, 5.63, 10.04                                                                      70.79, 5.48,                                                                            698, M.sup.+        I-24                                                                               H                                                                                  ##STR33##                                                                             (Ph).sub.2 CH                                                                       H  2-(1H- tetrazol- 5-yl)Ph                                                            H  H  C.sub.39 H.sub.36 N.sub.8 O.sub.3                                                     70.46, 5.46, 16.86                                                                      70.55, 5.40,                                                                            665, M.sup.+        I-25                                                                               nPr                                                                                ##STR34##                                                                             (Ph).sub.2 CH                                                                       H  2-(1H- tetrazol- 5-yl)Ph                                                            H  H  C.sub.42 H.sub.42 N.sub.8 O.sub.3                                                     71.37, 5.99, 15.85                                                                      71.50, 5.92,                                                                            707, M.sup.+        I-26                                                                               iPr                                                                                ##STR35##                                                                             (Ph).sub.2 CH                                                                       H  2-(1H- tetrazol- 5-yl)Ph                                                            H  H  C.sub.42 H.sub.42 N.sub.8 O.sub.3                                                     71.37, 5.99, 15.85                                                                      71.46, 5.98,                                                                            707, M.sup.+        I-27                                                                               nBu                                                                               CH.sub.2 OH                                                                            (Ph).sub.2 CH                                                                       H  COOH H  H  C.sub.33 H.sub.35 N.sub.3 O.sub.4                                                     73.72, 6.56, 7.82                                                                       73.91, 6.49,                                                                            538, M.sup.+        I-28                                                                               nBu                                                                               COOH    (Ph).sub.2 CH                                                                       H  COOH H  H  C.sub.33 H.sub.33 N.sub.3 O.sub.5                                                     71.85, 6.03, 7.62                                                                       72.01, 5.98,                                                                            552, M.sup.+        I-29                                                                               nBu                                                                                ##STR36##                                                                             (Ph).sub.2 CH                                                                       H  COOH H  H  C.sub.37 H.sub.40 N.sub.4 O.sub.5                                                     71.59, 6.49, 9.03                                                                       71.66, 6.39,                                                                            621, M.sup.+        I-30                                                                               nBu                                                                                ##STR37##                                                                             (Ph).sub.2 CH                                                                       Me NHCO (2- COOH- Ph)                                                                  H  H  C.sub.45 H.sub.47 N.sub.5 O.sub.6                                                     71.69, 6.28, 9.29                                                                       71.77, 6.20,                                                                            754, M.sup.+        I-31                                                                               nBu                                                                                ##STR38##                                                                             (Ph).sub.2 CH                                                                       H  2-(1H- tetrazol- 5-yl)Ph                                                            H  H  C.sub.43 H.sub.44 N.sub.8 O.sub.3                                                     71.65, 6.15, 15.54                                                                      71.79, 6.10,                                                                            721, M.sup.+        I-32                                                                               nBu                                                                                ##STR39##                                                                             (Ph).sub.2 CH                                                                       H  2-(1H- tetrazol- 5-yl)Ph                                                            H  H  C.sub.43 H.sub.44 N.sub.8 O.sub.2                                                     70.08, 6.02, 15.21                                                                      70.20, 5.98,                                                                            737, M.sup.+        __________________________________________________________________________

                                      TABLE 19                                     __________________________________________________________________________     Com-                                                                           pound                            Elementary                                                                            Calcd. for                                                                              Found    MS                   No. R.sup.1                                                                           R.sup.2  R.sup.3                                                                             R.sup.4                                                                          R    R.sup.7                                                                          R.sup.8                                                                           analysis                                                                              (C, H, N) (%)                                                                           (C, H, N)                                                                               (FAB)                __________________________________________________________________________     I-33                                                                               nBu                                                                                ##STR40##                                                                              (Ph).sub.2 CH                                                                       H 2-(1H- tetrazol- 5-yl)Ph                                                            H H  C.sub.43 H.sub.45 N.sub.9 O.sub.2                                                     71.74, 6.30, 17.51                                                                      71.89, 6.18,                                                                            720, M.sup.+         I-34                                                                               nBu                                                                                ##STR41##                                                                              (Ph).sub.2 CH                                                                       H 2-(1H- tetrazol- 5-yl)Ph                                                            H H  C.sub.42 H.sub.42 N.sub.8 O.sub.2                                                     73.02, 6.13, 16.22                                                                      73.18, 6.09,                                                                            691, M.sup.+         I-35                                                                               nBu                                                                                ##STR42##                                                                              (Ph).sub.2 CH                                                                       H 2-(1H- tetrazol- 5-yl)Ph                                                            H H  C.sub.43 H.sub.44 N.sub.8 O.sub.2                                                     73.27, 6.29, 15.90                                                                      73.45, 6.18,                                                                            705, M.sup.+         I-36                                                                               nBu                                                                                ##STR43##                                                                              (Ph).sub.2 CH                                                                       H 2-(1H- tetrazol- 5-yl)Ph                                                            H H  C.sub.44 H.sub.46 N.sub.8 O.sub.2                                                     73.51, 6.45, 15.59                                                                      73.51, 6.45,                                                                            719, M.sup.+         I-37                                                                               nBu                                                                               CONH.sub.2                                                                              (Ph).sub.2 CH                                                                       H 2-(1H-                                                                              H H  C.sub.39 H.sub.38 N.sub.8 O.sub.2                                                     71.98, 5.89, 17.22                                                                      72.10, 5.76,                                                                            651, M.sup.+                                tetrazol-                                                                      5-yl)Ph                                                 I-38                                                                               nBu                                                                               CONHMe   (Ph).sub.2 CH                                                                       H 2-(1H-                                                                              H H  C.sub.40 H.sub.40 N.sub.8 O.sub.2                                                     72.27, 6.06, 16.86                                                                      72.49, 5.98,                                                                            665, M.sup.+                                tetrazol-                                                                      5-yl)Ph                                                 I-39                                                                               nBu                                                                               CON(Me).sub.2                                                                           (Ph).sub.2 CH                                                                       H 2-(1H-                                                                              H H  C.sub.41 H.sub.42 N.sub.8 O.sub.2                                                     72.54, 6.24, 16.51                                                                      72.70, 6.18,                                                                            679, M.sup.+                                tetrazol-                                                                      5-yl)Ph                                                 I-40                                                                               nBu                                                                               CON(Et).sub.2                                                                           (Ph).sub.2 CH                                                                       H 2-(1H-                                                                              H H  C.sub.43 H.sub.46 N.sub.8 O.sub.2                                                     73.06, 6.56, 15.85                                                                      73.21, 6.48,                                                                            707, M.sup.+                                tetrazol-                                                                      5-yl)Ph                                                 I-41                                                                               nBu                                                                                ##STR44##                                                                              (Ph)(c- Hex)CH                                                                      H 2-(1H- tetrazol- 5-yl)Ph                                                            H H  C.sub.43 H.sub.50 N.sub.8 O.sub.3                                                     71.05, 6.93, 15,41                                                                      71.19, 6.90,                                                                            727, M.sup.+         I-42                                                                               nHex                                                                               ##STR45##                                                                              (Ph).sub.2 CH                                                                       H 2-(1H- tetrazol- 5-yl)Ph                                                            H H  C.sub.45 H.sub.46 N.sub.8 O.sub.3                                                     72.36, 6.21, 15.00                                                                      72.33, 6.39,                                                                            747,                 __________________________________________________________________________                                                               M.sup.+         

There were also similarly synthesized the compounds shown in Table 20.

                                      TABLE 20                                     __________________________________________________________________________     Compound No.                                                                           R.sup.1                                                                           R.sup.2 R.sup.3                                                                             R.sup.4                                                                           R.sup.7                                                                          R.sup.8                                                                          R.sup.10                                                                          MS(EI)                                       __________________________________________________________________________     I'-1    H                                                                                  ##STR46##                                                                             (Ph).sub.2 CH                                                                       Me H H NH.sub.2                                                                          550(M.sup.+)                                 I'-2    nBu                                                                                ##STR47##                                                                             (Ph).sub.2 CH                                                                       Me H H NH.sub.2                                                                          606(M.sup.+)                                 __________________________________________________________________________                       Calcd. for                                                   Compound No.                                                                           Elementary analysis                                                                      (C, H, N) (%)                                                                            Found (C, H, N) (%)                                __________________________________________________________________________     I'-1    C.sub.33 H.sub.35 N.sub.5 O.sub.3                                                        72.11, 6.42, 12.74                                                                       72.21, 6.35, 12.66                                 I'-2    C.sub.37 H.sub.43 N.sub.5 O.sub.3                                                        73.36, 7.15, 11.56                                                                       73.51, 7.02, 11.47                                 __________________________________________________________________________

EXAMPLE 28 Process B, Step (o) Synthesis of (S)-3-(2-n-butyl-1-triphenylmethyl-imidazol-5-yl)-2-(triphenylmethylamino)propan-1-ol (XXIV-3)

A 1.0M (nBu)₄ NF/THF solution (2.6 ml, 0.00258 mol) was added to a solution of the compound (XIX-3) in dry THF (10 ml) with stirring under ice cooling, and the mixture was stirred under ice cooling for 30 minutes and further at room temperature for 3 hours. The reaction mixture was poured into water and extracted with EtOAc. The organic layer was washed with a saturated NaCl aqueous solution, dried over Na₂ SO₄, and concentrated to obtain a white foamy material (1.0896 g, 100% up). This material was purified by silica gel column chromatography (hexane/acetone=5/1) to obtain the objective compound (XXIV-3) (0.7912 g; yield: 89.8%) as a white foamy material.

¹ H-NMR (CD₂ Cl₂) δ: 0.59 (t, 3H, J=7.3 Hz), 0.91 (sext, 2H, J=7.3 Hz), 1.11 (quint, 2H, J=7.3 Hz), 1.55 (bs, 1H, OH), 1.78-1.85 (m, 3H), 2.03 (b, 1H, NH), 2.23 (dd, 1H, J=3.2, 14.4 Hz), 2.80 (b, 1H, CH), 2.95 (dd, 1H, J=6.4, 11.5 Hz), 3.48 (dd, 1H, J=3.2, 11.5 Hz), 6.14 (s, 1H), 7.10-7.51 (m, 30H).

IR (ν_(max), KBr): 3452, 3105, 2900, 2975, 2905, 1510, 1456, 1410, 1160, 1036, 766, 744, 702, 640 cm⁻¹.

There were similarly synthesized the compounds shown in Table 21.

                                      TABLE 21                                     __________________________________________________________________________     Compound Elementary                                                            No.   R.sup.1                                                                           Analysis                                                                             Calcd. for (C, H, N) (%)                                                                    Found (C, H, N) (%)                                                                       MS(EI)                                  __________________________________________________________________________     XXIV-1                                                                               nPr                                                                               C.sub.47 H.sub.45 N.sub.3 O                                                          84.52, 6.79, 6.29                                                                           84.71, 6.66, 6.10                                                                         668                                     XXIV-2                                                                               iPr                                                                               C.sub.47 H.sub.45 N.sub.3 O                                                          84.52, 6.79, 6.29                                                                           84.69, 6.71, 6.11                                                                         668                                     XXIV-3                                                                               nBu                                                                               C.sub.48 H.sub.47 N.sub.3 O                                                          84.54, 6.95, 6.16                                                                           84.70, 6.84, 6.08                                                                         682                                     XXIV-4                                                                               nHex                                                                              C.sub.50 H.sub.51 N.sub.3 O                                                          84.59, 7.24, 5.92                                                                           84.72, 7.15, 5.88                                                                         710                                     __________________________________________________________________________

EXAMPLE 29 Process B, Step (p) Synthesis of (S)-3-(2-n-butyl-1-triphenylmethyl-imidazol-5-yl)-2-(triphenylmethylamino) propanoic acid (XXV-3)

PDC (0.7845 g, 0.00208 mol) was added to a solution of the compound (XXIV-3) (0.4063 g, 0.000596 mol) in DMF (4.0 ml) and stirred at room temperature for 8 hours. The reaction mixture was poured into water and extracted with CH₂ Cl₂. The organic layer was washed with water and then with a saturated NaCl aqueous solution, dried over Na₂ SO₄, and concentrated to obtain a reddish brown oily product (0.5745 g, 100% up). This product was purified by silica gel column chromatography (hexane/acetone=2/1→1/2 and CHCl₃ /MeOH=30/1) to obtain the objective compound (XXV-3) (0.1256 g; yield: 39.3%) as a light-yellow oily material.

¹ H-NMR (CDCl₃) δ: 0.59 (t, 3H, J=7.3 Hz), 0.91 (sext, 2H, J=7.3 Hz), 1.16 (quint, 2H, J=7.3 Hz), 1.68-1.79 (m, 3H), 2.31 (dd, 1H, J=9.1, 15.3 Hz), 3.53 (d, 1H, J=9.1 Hz), 5.93 (s, 1H), 7.04-7.45 (m, 30H).

IR (ν_(max), KBr): 3025, 2980, 1715, 1608, 1510, 1460, 1410, 1390, 1370, 1190, 1158, 910, 730, 703 cm⁻¹.

The compounds shown in Table 22 were synthesized in the similar way.

                                      TABLE 22                                     __________________________________________________________________________     Compound Elementary                                                            No.   R.sup.1                                                                           analysis                                                                              Calcd. for (C, H, N) (%)                                                                    Found (C, H, N) (%)                                                                       MS(FAB)                                __________________________________________________________________________     XXV-1 nPr                                                                               C.sub.47 H.sub.43 N.sub.3 O.sub.2                                                     82.79, 6.36, 6.16                                                                           82.93, 6.27, 6.03                                                                         682(M.sup.+)                           XXV-2 iPr                                                                               C.sub.47 H.sub.43 N.sub.3 O.sub.2                                                     82.79, 6.36, 6.16                                                                           82.88, 6.29, 6.08                                                                         682(M.sup.+)                           XXV-3 nBu                                                                               C.sub.48 H.sub.45 N.sub.3 O.sub.2                                                     82.85, 6.52, 6.04                                                                           83.01, 6.44, 5.95                                                                         696(M.sup.+)                           XXV-4 nHex                                                                              C.sub.50 H.sub.49 N.sub.3 O.sub.2                                                     82.95, 6.82, 5.80                                                                           83.11, 6.74, 5.68                                                                         724(M.sup.+)                           __________________________________________________________________________

EXAMPLE 30 Process B, Step (q) Synthesis of (S)-2-amino-3-(2-n-butyl-1H-imidazol-5-yl)propanoic acid (XXV'-3) and (S)-2-n-butyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid hydrochloride (XXVI-3)

A 1N HCl aqueous solution (3.3 ml) and a 37% HCHO solution (0.2 ml) were added to the compound (XXV-3) (0.3308 g, 0.000475 mol) and stirred at room temperature for 40 minutes and then in a 120° C. oil bath for 4 hours. After the reaction mixture was cooled, the insoluble portion was filtered out and washed with water. The aqueous layer was washed with Et₂ O, then concentrated, and dried to obtain the objective compound (XXVI-3) (0.1401 g; yield: 99.5%) as a yellow viscous material.

¹ H-NMR (D₂ O+NaOD) δ: 0.95 (t, 3H, J=7.3 Hz), 1.40 (sext, 2H, J=7.3 Hz), 1.80 (quint, 2H, J=7.3 Hz), 3.03 (t, 2H, J=7.3 Hz), 3.0-3.4 (m, 2H), 3.8-4.3 (m, 2H).

MS (FAB): 223 (M-2HCl)

The compounds shown in Table 23 were similarly synthesized.

                  TABLE 23                                                         ______________________________________                                         Compound No.     R.sup.1                                                                               MS (FAB)                                               ______________________________________                                         XVIII-1          nPr    209 (M-2HCl)                                           XVIII-2          iPr    209 (M-2HCl)                                           XVIII-3          nBu    223 (M-2HCl)                                           XVIII-4          nHex   251 (M-2HCl)                                           ______________________________________                                    

By using the compound (XXV-3) (0.3001 g, 0.000431 mol) and a 1N HCl aqueous solution (3.0 ml), the above reaction procedure was repeated without adding the 37% HCHO solution to obtain the compound (XXV'-3) (0.1225 g; yield: 100%) as a yellow viscous material.

¹ H-NMR (D₂ O+NaOD) δ: 0.96 (t, 3H, J=7.3Hz), 1.39 (sext, 2H, J=7.3Hz), 1.82 (quint, 2H, J=7.3Hz), 2.5-3.7 (m, 3H), 3.07 (t, 2H, J=7.3Hz), 6.85 (bs, 1H).

MASS (FAB): 211 (M-2HCl)

There were similarly synthesized the compounds shown in Table 24.

                  TABLE 24                                                         ______________________________________                                         Compound No.     R.sup.1                                                                               MS (FAB)                                               ______________________________________                                         XXV'-1           nPr    197 (M-2HCl)                                           XXV'-2           iPr    197 (M-2HCl)                                           XXV'-3           nBu    211 (M-2HCl)                                           XXV'-4           nHex   239 (M-2HCl)                                           ______________________________________                                    

EXAMPLE 31 Process B, Step (r) Synthesis of (S)-2-n-butyl-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid (XXVII-3)

Diphenylacetic acid (0.3114 g, 0.00147 mol), DCCI (0.3027 g, 0.00147 mol), and HBTA (0.1983 g, 0.00147 mol) were dissolved in dry THF (0.8 ml) and stirred at room temperature for 20 minutes. A solution of the compound (XXVI-3) (0.1358 g, 0.000458 mol) in dry THF (2.7 ml), and dry triethylamine (0.13 ml, 0.000963 mol) were added to this mixture, followed by stirring at room temperature for 16 hours. The insoluble portion was filtered out and washed with THF. The filtrate and washings were joined and concentrated to obtain a crude oily product (0.3065 g). This product was dissolved in a 1/1 mixture of THF and MeOH (6.0 ml) and, after addition of a 1N HCl aqueous solution (2.0 ml), left as it was for 8 hours. Further a 1/1 mixture of THF and MeOH (6.0 ml) and a 1N NaOH aqueous solution (4.0 ml) were added, and the mixture was left as it was for 8 hours. The reaction mixture was concentrated and the residue was purified by silica gel column chromatography (chloroform/methanol=10/1) to obtain the objective compound (XXVII-3) (0.0829 g; yield: 43.3%) as a white foamy material.

¹ H-NMR (D₂ O+NaOD) δ: 0.92 (t, 3H, J=7.2 Hz), 1.39 (sext, 2H, J=7.2 Hz), 1.82 (quint, 2H, J=7.2 Hz), 2.3-2.9 (m, 4H), 3.9-4.8 (m, 2H), 5.51 (s, 1H), 5.73 (bs, 1H), 7.1-7.7 (m, 10H).

MASS (FAB): 417 (M⁺)

Elementary analysis Calcd. for C₂₅ H₂₇ N₃ O₃ (%): C, 71.92; H, 6.52; N, 10.06. Found: C, 72.08; H, 6.47; N, 9.99.

The compounds shown in Table 25 were similarly synthesized.

                                      TABLE 25                                     __________________________________________________________________________     Compound         Elementary                                                                            Calcd. for                                             No.   R.sup.1                                                                           R.sup.3 analysis                                                                              (C, H, N) (%)                                                                             Found (C, H, N) (%)                                                                       MS(FAB)                          __________________________________________________________________________     XXVII-1                                                                              nPr                                                                               (Ph).sub.2 CH                                                                          C.sub.24 H.sub.25 N.sub.3 O.sub.3                                                     71.44,                                                                             6.25,                                                                             10.41                                                                              71.61,                                                                             6.17,                                                                             10.35                                                                              403(M.sup.+)                     XXVII-2                                                                              iPr                                                                               (Ph).sub.2 CH                                                                          C.sub.24 H.sub.25 N.sub.3 O.sub.3                                                     71.44,                                                                             6.25,                                                                             10.41                                                                              71.59,                                                                             6.19,                                                                             10.37                                                                              403(M.sup.+)                     XXVII-3                                                                              nBu                                                                               (Ph).sub.2 CH                                                                          C.sub.25 H.sub.27 N.sub.3 O.sub.3                                                     71.92,                                                                             6.52,                                                                             10.06                                                                              80.07,                                                                             6.48,                                                                             9.98                                                                               417(M.sup.+)                     XXVII-4                                                                              nHex                                                                              (Ph).sub.2 CH                                                                          C.sub.27 H.sub.31 N.sub.3 O.sub.3                                                     72.78,                                                                             7.01,                                                                             9.43                                                                               72.91,                                                                             6.94,                                                                             9.35                                                                               446(M.sup.+)                     XXVII-5                                                                              nBu                                                                               (Ph)(c-Hex)CH                                                                          C.sub.25 H.sub.33 N.sub.3 O.sub.3                                                     70.89,                                                                             7.85,                                                                             9.92                                                                               71.01                                                                              7.78                                                                              9.85                                                                               424(M.sup.+)                     __________________________________________________________________________

EXAMPLE 32 Process B, Step (s) Synthesis of (S)-2-n-butyl-1-[(4-methoxycarbonylphenyl)methyl]-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid (XIV-8)

Methyl 4-(bromomethyl)benzoate (0.0521 g, 0.000227 mol) and K₂ CO₃ (0.0314 g, 0.000227 mol) were added to a solution of the compound (XXVII-3) (0.0791 g, 0.000189 mol) in dry DMF (1.6 ml), and the mixture was stirred vigorously at room temperature for 20 hours. The reaction mixture was poured into water, extracted with EtOAc, washed with water, dried over anhydrous sodium sulfate, and concentrated to obtain a light-yellow oily material. This material was purified by silica gel column chromatography (hexane/acetone=1/2) to obtain the objective compound (XIV-8) (0.0331g; m.p. 176°-180° C.), its 3-position isomer (0.0382 g) and a mixture of them (0.0018 g; yield: 68.2%) as colorless crystals.

MASS (FAB): 566 (M⁺)

Elementary analysis Calcd. for C₃₄ H₃₅ N₃ O₅ (%): C, 72.19; H, 6.24; N, 7.43. Found: C, 72.30; H, 6.21; N, 7.39.

EXAMPLE 33

Receptor binding test

Determination of total binding in the presence of each drug to be tested was made in the following way. A test drug of a predetermined concentration (0.025 ml; dissolved in dimethyl sulfoxide, then diluted two-fold with a buffer attached to the Drug Discovery System and used for assay), a tracer (0.025 ml), and a receptor (0.2 ml) were added to make a total volume of 0.25 ml. After incubation (at room temperature for 3 hours for the angiotensin II receptor type 1 (AT₁) and at 37° C. for one hour for the type 2 (AT₂)), the reaction mixture was subjected to suction filtration (using GF/C filter paper for AT₁ and GF/B filter paper for AT₂). The filter paper (tracer-receptor complex) after suction filtration was measured by a y-well counter (ARC-500, Aloka). The non-specific binding was determined by the similar operation by using a large excess of displacer. The specific binding at the predetermined concentration of the test drug was calculated by deducting the non-specific binding from the total binding.

The ratio (%) at which the test drugs inhibit binding between radioactive ligand and receptor was determined for both AT₁ and AT₂ by using the test drugs of the predetermined concentration and a control drug.

The compound of the present invention competes with both of the angiotensin II receptors AT₁ and AT₂, but it is noted that the compound of the formula (I) wherein R₁ is H competes specifically with AT₂ and that of the formula (I) wherein R₁ is other than H competes specifically with AT₁.

In U.S. Pat. No. 5,091,390, it is stated that the compounds claimed therein, including some reference compounds described below, compete selectively with AT₂ regardless of R¹, but the present inventors found that the compound of the present invention and the reference compounds compete specifically with one of AT₁ and AT₂ receptors according to the difference of R¹, and that the activity of the compound of the present invention far excels that of the reference compounds.

                  TABLE 26                                                         ______________________________________                                         Binding inhibition ratio (%) of the test                                       compounds at 1 μM                                                           Test compound      AT.sub.1 *                                                                             AT.sub.2 **                                         ______________________________________                                         Compound I-1       0       100                                                 Compound I-2       0       100                                                 Compound I-7       0       100                                                 Compound I-12      100     0                                                   Compound I-17      100     0                                                   Compound I-19      100     0                                                   Compound I-21      0       100                                                 Compound I-23      0       100                                                 Compound I-24      0       100                                                 Compound I-30      100     0                                                   Compound I-31      100     0                                                   Compound I-32      100     0                                                   Compound I-40      100     0                                                   Reference compound 0       65                                                  PD123177                                                                       Reference compound 70      0                                                   DuP753                                                                         Reference compound 1                                                                              0       71                                                  Reference compound 2                                                                              0       72                                                  Reference compound 26                                                                             78      0                                                   Reference compound 27                                                                             0       76                                                  Reference compound 50                                                                             75      0                                                   ______________________________________                                          *Receptor: suprarenal gland of rabbit Tracer: .sup.3 Hangiotensin II           (displacer: DuP753)                                                            **Receptor: bovine cerebellar cortex Tracer: .sup.125 ITyr.sup.4               -angiotensin II (displacer: angiotensin II (human))                      

PD123177 and DuP753 are disclosed in Bioorganic & Medical Chemistry Letters, 1(12), 711-716, 1991. ##STR48##

Comparative substances 1, 2, 26, 27 and 50 are the compounds disclosed in U.S. Pat. No. 5,091,390:

    __________________________________________________________________________      ##STR49##                                                                     Reference compound                                                                        R.sup.1                                                                           R.sup.2                                                                              R.sup.3                                                                               X     R.sup.4                                                                             R.sup.6                                  __________________________________________________________________________      1         H  COOH  COCH(Ph).sub.2                                                                        NHCO  COOH 3-CH.sub.3                                2         H  COOCH.sub.3                                                                          COCH(Ph).sub.2                                                                        NHCO  COOH 3-CH.sub.3                               26         C.sub.3 H.sub.7                                                                   COOH  COCH(Ph).sub.2                                                                        single bond                                                                          tetrazolyl                                                                          3-CH.sub.3                               27         H  COOH  COCH(Ph).sub.2                                                                        single bond                                                                          tetrazolyl                                                                          H                                        50         C.sub.3 H.sub.7                                                                   COOH  COCH(Ph).sub.2                                                                        single bond                                                                          tetrazolyl                                                                          H                                        __________________________________________________________________________ 

What is claimed is:
 1. A compound of the formula (I): ##STR50## or a pharmaceutically acceptable salt thereof; wherein R¹ representshydrogen atom, halogen atom, C₁ -C₆ alkyl, C₃ -C₆ alkenyl, C₃ -C₆ alkynyl, R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6, R²⁰ --C(O)-- wherein R²⁰ is as defined above, or R²⁰ --CH(OH)-- wherein R²⁰ is as defined above; R² represents carbamoyl, mono- or di-C₁ -C₆ alkylcarbamoyl, or 4- to 6-membered saturated N, S or O-containing heterocyclic carbamoyl; R represents amino, carboxy, (1H-tetrazol-5-yl)phenyl, carboxyphenyl, carboxybenzamido, (1H-tetrazol-5-yl)benzamido, carboxyphenylcarbamoyl, or (1H-tetrazol-5-yl)-phenylcarbamoyl; represents --CH₂ (phenyl), --CH(phenyl)₂, --CH(phenyl)CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl); and R⁴, R⁷, and R⁸ each represent independently hydrogen atom or C₁ -C₆ alkyl.
 2. A compound or a pharmaceutically acceptable salt thereof according to claim 1, wherein R¹ is hydrogen atom or C₁ -C₆ alkyl group; R² is --CONH₂, --CONHCH₃, --CON(CH₃)₂, --CONH(C₂ H₅), --CON(C₂ H₅)₂, ##STR51## R is amino, carboxy, 2-(1H-tetrazol-5-yl)phenyl, 2-carboxyphenyl, 2-carboxybenzamido, 2-(1H-tetrazol-5-yl)benzamido, 2-carboxyphenylcarbamoyl, or 2-(1H-tetrazol-5-yl)phenylcarbamoyl; R³ is --CH(phenyl)₂, --CH₂ (phenyl), --CH(phenyl)CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (p-methoxyphenyl), or --CH₂ (p-hydroxyphenyl); and R⁴, R⁷, and R⁸ each are independently hydrogen atom or C₁ -C₂ alkyl.
 3. A compound of the formula (XIII): ##STR52## or a salt thereof; wherein R¹ representshydrogen atom, halogen atom, C₁ -C₆ alkyl, C₃ -C₆ alkenyl, C₃ -C₆ alkynyl, R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6, R²⁰ --C(O)-- wherein R²⁰ is as defined above, or R²⁰ --CH(OH)-- wherein R²⁰ is as defined above; R^(2') represents amino, mono or di-C₁ -C₆ alkylamino, or 4- to 6-membered saturated N, S or O-containing heterocyclic amino; R³ represents --CH₂ (phenyl), --CH(phenyl)₂, --CH(phenyl) CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl); R⁴, R⁷, and R⁸ each represent independently hydrogen atom or C₁ -C₆ alkyl; and R⁶ represents nitro, (1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, C₁ -C₃ alkoxycarbonyl, cyano, or 2-cyanophenyl.
 4. A compound or a salt thereof according to claim 3, wherein R¹ is hydrogen atom or C₁ -C₆ alkyl; R² is --NH₂, --NHCH₃, --N(CH₃)₂, --NH(C₂ H₅), N(C₂ H₅)₂, ##STR53## R³ is --CH(phenyl)₂, --CH(phenyl)(cyclohexyl); R⁴, R⁷, and R⁸ each are independently hydrogen atom or C₁ -C₂ alkyl; and R⁶ is nitro, 2-(1-triphenylmethyl-1H-tetrazol-5-yl)phenyl, methoxycarbonyl, cyano, or 2-cyanophenyl.
 5. An angiotensin II antagonist comprising the compound or the pharmaceutically acceptable salt thereof as defined in claim
 1. 6. An angiotensin II AT₁ receptor antagonist comprising a compound of the formula (I): ##STR54## or a pharmaceutically acceptable salt thereof; wherein R¹ representshalogen atom, C₁ -C₆ alkyl, C₃ -C₆ alkenyl, C₃ -C₆ alkynyl, R²⁰ (CH₂)_(n) -- wherein R²⁰ represents C₃ -C₈ cycloalkyl, naphthyl, phenyl, or phenyl substituted with one to five of C₁ -C₄ alkyl, halogen atom, trifluoromethyl, hydroxy, C₁ -C₄ alkoxy, C₁ -C₃ acyloxy, amino, N-mono-C₁ -C₄ alkylamino, N-di-C₁ -C₄ alkylamino, C₁ -C₄ thioalkyl, C₁ -C₃ alkylsulfonyl, nitro, and --NHCOR²¹ wherein R²¹ represents C₁ -C₃ alkyl, phenyl, C₁ -C₃ alkylphenyl, aminophenyl, or C₁ -C₄ alkylaminophenyl, and n is an integer of 1 to 6, R²⁰ --C(O)-- wherein R²⁰ is as defined above, or R²⁰ --CH(OH)-- wherein R²⁰ is as defined above; R² represents carbamoyl, mono- or di-C₁ -C₆ alkylcarbamoyl, or 4- to 6-membered saturated N, S, or O-containing heterocyclic carbamoyl; R represents amino, carboxy, (1H-tetrazol-5-yl)phenyl, carboxyphenyl, carboxybenzamido, (1H-tetrazol-5-yl)benzamido, carboxyphenylcarbamoyl, or (1H-tetrazol-5-yl)-phenylcarbamoyl;R³ represents --CH₂ (phenyl), --CH(phenyl)₂, --CH(phenyl) CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl); and R⁴ R⁷, and R⁸ each represent independently hydrogen atom or C₁ -C₆ alkyl.
 7. An angiotensin II AT₂ receptor antagonist comprising a compound of the formula (I): ##STR55## or a pharmaceutically acceptable salt thereof; wherein R¹ represents hydrogen atom,R² represents carbamoyl, mono- or di-C₁ -C₆ alkylcarbamoyl, or 4- to 6-membered saturated N, S, or O-containing heterocyclic carbamoyl; R represents amino, carboxy, (1H-tetrazol-5-yl)phenyl, carboxyphenyl, carboxybenzamido, (1H-tetrazol-5-yl)benzamido, carboxyphenylcarbamoyl, or (1H-tetrazol-5-yl)-phenylcarbamoyl; R³ represents --CH₂ (phenyl), --CH(phenyl)₂, --CH(phenyl)CH₃, --CH(phenyl)(cyclohexyl), --CH₂ CH₂ (phenyl), --CH₂ (C₁ -C₆ alkoxyphenyl), or --CH₂ (hydroxyphenyl); and R⁴, R⁷, and R⁸, each represent independently hydrogen atom or C₁ -C₆ alkyl. 